ISOLATED GENES AND PROTEINS ENCODING RESISTANCE TO PHOTOSENSITIZERS

Abstract: The present invention is drawn to methods and compounds for providing resistance to photosensitizers in cells and organisms that are sensitive to photosensitizers. Specifically, an isolated nucleic acid molecule, which upon expression provides resistance to a photosensitizer, is described. Also described are methods of transforming cells and organisms with the isolated nucleic acid molecule, such that resistance to a photosensitizer is increased or provided to the cells and organisms so transformed.

Description: ISOLATED GENES AND PROTEINS ENCODING RESISTANCE TO PHOTOSENSITIZERS FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with government support under grant numbers MCB-9205578 and MCB-9631375 from the National Science Foundation, and NRI Competitive Grant number 9601197 from the USD A. BACKGROUND OF THE INVENTION Cercospora species are a highly successful group of fungal pathogens that cause disease on a diversity of host plants, including corn, sugar beet, tobacco, coffee, soybean, and banana, as well as many ornamental and weed species. For example, the Cercospora species C. nicotiniae, C. arachidicola, C. zeae-maydis, C. kikuchii, C. oryzae and C. beticola are pathogenic to tobacco, peanut, corn, soybean, rice and sugar beet, respectively. The Cercospora species are aerial pathogens. In general, spores produced by these fungi germinate on leaf surfaces and then enter the leaf (i.e. through stomata). Fungal mycelium then kills leaf cells and causes severe blighting of the leaf tissue by spreading through intercellular spaces in leaf tissues. See M.E. Daub, American Chemical Society Symposium Series No. 339, pp. 271-80 (J.R. Heitz and K.R. Downum, eds. , Washington, D.C. , 1987). In addition to damaging leaf tissue, Cercospora species may also damage other plant tissues, such as the seed coat in soybean. Cercospora species cause major economic problems due not only to their world-wide distribution and wide host range, but also because naturally-occurring resistance to the disease has not been identified in many host species. One of the reasons for the success of this group of pathogens appears to be their production of cercosporin, a perylenequinone phytotoxin and a photosensitizer. Cercosporin is produced by many members of the genus Cercospora, and has near universal toxicity to plants. Cercosporin is also toxic to mice, bacteria, and many fungi. See R.B. Batcharova et al. , Phytopathology 82, 642-46 (1992); C. Balis and M.G. Payne Phytopathology 61, 1477-84 (1971); M.E. Daub Phytopathology 11, 1515-20 (1987); A.O. Fajola, Physiol. Plant. Pathol. 13, 157-64 (1978); S. Yamazaki et al. , Agric. Biol. Chem. 39, 287-88 (1975). Cercosporin has additionally been shown inactivate protein kinase C and to be cytotoxic to human tumor cells. See T. Tamaoki and H. Nakano Bio /Technology 8, 732-35 (1990). These observations suggest that cercosporin has almost universal toxicity to cells, and that resistance is due to active defense mechanisms present in the few resistant organisms. Production of cercosporin appears critical for successful patho genesis, as fungal mutants deficient in cercosporin synthesis are unable to parasitize their host plants (R.G. Upchurch et al. , Appl. Envir. Biol. 57, 2940-45 (1991)). The presence of light has been shown to be critically important in the development of disease symptoms on hosts susceptible to Cercospora infection, and symptom development in infected plants is enhanced by high light intensities. See, e.g. , M.E. Daub and M. Ehrenshaft, Physiol. Plant 89, 227-36 (1993); L. Calpouzos, Ann. Rev. Phytopathol. 4, 369-390 (1967). The role of cercosporin as a photosensitizer is thus related to its ability to cause toxicity and injury in cells. Although cercosporin was the first toxin synthesized by plant pathogens to be recognized as a photosensitizer, numerous other plant pathogenic fungi also produce perylenequinone toxins and other compounds that are photosensitizers. The production of photoactivated perylenequinones by such a diversity of plant pathogens suggests that photosensitization may be a more common plant pathogenesis factor than has been previously recognized. Virtually the only organisms which show resistance to cercosporin are the Cercospora fungi themselves, and some related fungi that produce similar toxins. Attempts to obtain resistant plants and fungi through mutagenesis and selection of cells in culture have not been successful. M. Ehrenshaft et al. , (Phytopathology 86, Sl l (Abstract 93A) (Supplement 1996)) report using a wild type C. nicotianae genomic library to isolate cosmid clones that complement two classes of C. nicotianae mutants which are sensitive to cercosporin. Transformation of the mutants with one of the clones restored wild type resistance to cercosporin and other photosensitizers. However, isolation and sequencing of the specific genes responsible for the resistance to the photosensitizers is not described therein. It would thus be highly desirable to isolate genes which encode resistance to photosensitizers such as cercosporin. Moreover, it would be desirable to provide plants and other organisms resistant to diseases caused by Cercospora species and other pathogenic fungi that produce photosensitizers. SUMMARY OF THE INVENTION A first aspect of the present invention is an isolated nucleic acid molecule that, upon expression, provides or increases resistance to a photosensitizer in a cell. A further aspect of the present invention is an isolated nucleic acid molecule that, upon expression, provides or increases resistance to cercosporin in a cell. A further aspect of the invention is a transformed cell comprising a chimeric gene, the gene comprising a nucleic acid molecule of the present invention operably linked with a promoter. A further aspect of the invention is a method for increasing resistance to a photosensitizer in cell, comprising transforming the cell with a nucleic acid molecule of the present invention. A further aspect of the invention is a method of increasing resistance in a cell to a pathogen, comprising transforming the cell with a nucleic acid of the present invention. A further aspect of the invention is a method of increasing resistance in a cell to singlet oxygen comprising transforming the cell with a nucleic acid of the present invention. A further aspect of the invention is an expression cassette comprising a chimeric gene, the gene comprising a nucleic acid molecule of the present invention operably linked with a promoter. A further aspect of the invention is a transformed plant, comprising either an expression cassette of the present invention, or a chimeric gene as described above. An further aspect of the present invention is a method for increasing resistance to a photosensitizer in plant, comprising transforming the plant with an expression cassette of the present invention. A further aspect of the invention is a method of increasing resistance in a plant to infection by a fungal pathogen, comprising transforming the plant with an expression cassette of the present invention. A further aspect of the present invention is a method of selecting transformed fungal or plant cells, using a transformation construct that includes a nucleic acid molecule of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 sets forth the nucleotide sequence of the Cercospora nicotianae gene sorl that encodes resistance to cercosporin (SEQ ID NO:l). FIGURE 2 sets forth the amino acid sequence of a polypeptide that provides resistance to cercosporin and which is encoded by the Cercospora nicotianae gene sorl (SEQ ID NO:2). FIGURE 3A sets forth the partial nucleotide sequence of the homologue to the C. nicotianae sorl gene isolated from Alternaria alternata (SEQ ID NO:3). FIGURE 3B sets forth the predicted partial amino acid sequence (SEQ ID NO:4) of the protein encoded by the Alternaria alternata nucleic acid sequence set forth in FIGURE 3 A. The predicted amino acid sequence represents the C-terminus of the protein encoded by the A. alternata gene. FIGURE 4A sets forth the alignment between the partial nucleotide sequence of the A. alternata gene (SEQ ID NO:3) and a fragment of the C. nicotianae sorl gene (SEQ ID NO:5). "AA1T7" indicates the A. alternata gene sequence, while "CSG" indicates the C. nicotianae sorl gene fragment sequence. The " = " sign between the two sequences indicates that the aligned residues are identical. FIGURE 4B sets forth the alignment between the predicted C- terminus amino acid sequence of the A. alternata gene (SEQ ID NO:6) and a fragment of the C. nicotianae sorl gene (SEQ ID NO:7). "AAHOMOLOG" represents the amino acid sequence of a portion of the A. alternata gene; "MAYBE2" represents the amino acid sequence of a fragment of the C. nicotianae sorl gene. The " = " sign indicates that aligned residues are identical, while the "-" sign indicates that the aligned residues are similar. "Similar" residues are as follows: A, S, and T are deemed similar to each other; D and E are similar; N and Q are similar; R and K are similar; I, L, M and V are similar; and F, Y and W are similar. FIGURE 4C sets forth the alignment between the predicted amino acid sequence of the A. alternata gene product (SEQ ID NO:ll) and the C. nicotianae sorl gene product (SEQ ID NO:2). The " = " sign indicates that aligned residues are identical, while the "-" sign indicates that the aligned residues are similar. "Similar" residues are as described above. DETAILED DESCRIPTION OF THE INVENTION The present invention now will be described more fully hereinafter with reference to the accompanying Figures, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Nucleotide sequences are presented herein by single strand only, in the 5Ao 3' direction, from left to right. Amino acid sequences disclosed herein are presented in the amino to carboxy direction, from left to right, unless otherwise indicated. The amino and carboxy groups are not presented in the sequence. Nucleotides and amino acids are represented herein in the manner recommended by the IUPAC-IUB Biochemical Nomenclature Commission. As used herein, the terms "protein" and "polypeptide" are used interchangeably, and refer to a polymer of amino acids (dipeptide or greater) linked through peptide bonds. Thus, the term "polypeptide" includes proteins, oligopeptides, protein fragments, protein analogs and the like. The term "polypeptide" contemplates polypeptides as defined above that are encoded by nucleic acids, are recombinantly produced, are isolated from an appropriate source, or are synthesized. As used herein, the term "photosensitizer" refers to a light-activated compound, which, in the presence of light, reacts with oxygen to produce compounds (e.g. , active oxygen species) that are damaging and toxic to cells. Photosensitizers are a group of structurally diverse compounds that have in common the ability to sensitize cells to light. More specifically, photosensitizers absorb light energy and are converted to an active state, which active state reacts with oxygen, either by radical reactions through a reducing substrate (type I reaction) or directly by an energy transfer mechanism (type II reaction). J.D. Spikes, The Science of Photobiology 2d. Edition, pp. 79-110 (K.C. Smith, ed., Plenum Press, New York 1989). Type I reactions lead to the production of a variety of reactive species, including a diversity of radical oxygen species such as superoxide (O 2 ), hydrogen peroxide (H 2 O 2 ), and the hydroxy radical (OH ). The Type II reaction leads to the production of one of the most reactive and toxic of the oxygen species, the active singlet state of oxygen (singlet oxygen or λ O_). Exposure of cells to photosensitizers and light may lead to the destruction of critical cellular components such as lipids, proteins and DNA, and often leads to cell death. Within the scope of the present invention, it is specifically intended that the term "photosensitizer" include compounds that react with oxygen through both Type I and Type II pathways, and include compounds that, upon exposure to light and reaction with oxygen, produce both radical forms of oxygen and the active singlet form of oxygen. Photosensitizer compounds as defined by the present invention may or may not be produced by pathogenic fungi. Singlet oxygen-generating photosensitizers that are produced by pathogenic fungi are, in general, perylenequinone toxins, and include, but are not limited to, cercosporin (produced by Cercospora spp. , e.g. , C. nicotianae, C. kikichii, C. oryzae); the elsinochromes (e.g., elsinochrome A, produced by species of Elsinoe and Sphaceloma); phleichrome (isolated from cucumbers infected with Cladosporium cucumerinum and from Cl. phlei and Cl. herbarum); the shiraiachromes (isolated from the bamboo pathogen Shiraia bambusicola); the hypocrellins (isolated from, e.g. , the bamboo pathogen Hypocrella bambusae); alteichin, alter toxins I, II, and III, and alter losin I and II (isolated from Alternaria spp.); stemphyltoxin III (isolated from Alternaria spp. and Stemphylium botryosum) and the perylenequinone toxins produced by the Scolecotrichum genera. See, e.g. , J.C. Over seem and A.K. Sijpesteijn, Phytochemistry 6, 99-105 (1967); D.J. Robeson and M.A.F. Jalal, Biosci. Biotech. Biochem. 56 949-52 (1992); H. Wu et al. , J. Nat. Products 5, 948- 51 (1989); V.M. Davis and M.E. Stack, Appl. Environ. Microbiol. 55, 7-14 (1991). Other photosensitizers, as defined in the present invention include the compounds rose bengal, hematoporphyrin, eosin Y, methylene blue and toluidine blue. The present invention is drawn to compositions and methods for providing or increasing cellular resistance to photosensitizers in organisms that are sensitive to photosensitizers. The compositions are proteins and the genes encoding them, which act to provide or increase cellular resistance to photosensitizers in such organisms. The proteins and the genes encoding resistance to photosensitizers, and the methods described herein that utilize these compounds, are useful in providing cellular resistance to pathogens that produce photosensitizers, and survival of these cells, particularly after pathogen attack. These same compositions and methods also provide or increase resistance to singlet oxygen itself. One aspect of the invention is drawn to proteins which are involved in providing resistance in a cell or an organism to a photosensitizer. The photosensitizer resistance proteins of the invention encompass a novel class of fungal proteins. The amino acid sequence of the photosensitizer resistance protein isolated from C. nicotianae is set forth in FIGURE 2 and is also provided herein as SEQ ID NO:2. However, the proteins are conserved in fungi and in other organisms. Thus, as discussed below, methods are available for the identification and isolation of genes and proteins from any organism. Likewise, sequence similarities can be used to identify and isolate other genes and proteins that encode resistance to photosensitizers. The proteins function to inhibit the spread of infection caused by pathogenic fungi that encode photosensitizers, and control resistance to such compounds in a number of organisms, including plants, bacteria, insects and animals. Therefore, the proteins are useful in a variety of settings involving the control of disease and toxicity resistance in plants and other organisms. Modifications of such proteins are also encompassed by the present invention. Such modifications include substitution of amino acid residues, deletions, additions, and the like. Accordingly, the proteins of the invention include naturally occurring fungal proteins and modifications thereof. The nucleotide sequences encoding the novel proteins are also provided. The gene sorl from C. nicotianae is set forth in FIG. 1 and provided herein as SEQ ID NO:l. This gene encodes the novel C. nicotianae protein, which confers resistance to several photosensitizers, including cercosporin. The C. nicotianae gene sorl can be utilized to isolate homologous genes from other organisms. For example, FIG. 2 provides the nucleotide sequence of an Alternaria alternata gene with significant sequence homology to C. nicotianae sorl, which A. alternata gene was isolated using the sorl gene. Nucleic acids and proteins of the present invention find use in preventing or increasing resistance in cells and organisms to photosensitizers. The proteins are also particularly useful in protecting organisms against pathogenic infection. In this manner, the organism is transformed with a nucleotide sequence encoding the protein. According to the present invention, organisms transformed in this manner may be plants, bacteria, fungi, and animals, with plants being preferred. The expression of the protein in the organism prevents toxicity and injury caused by photosensitizers, and confers or increases resistance to infection by fungal pathogens . Although the compounds and methods of the present invention are useful in providing resistance to infection by any fungal pathogen that produces a photosensitizer, the present invention finds particular use in providing protection against infection caused by (and photosensitizers produced by) the over 2,000 fungal pathogens of the Cercospora species. This group of fungal pathogens includes, but is not limited to: C. arachidicola (infecting peanuts), C. ariminiensis , C. asparagi (infecting asparagus), C. bertoreae, C. beticola (infecting sugar beets), C. bizzozeriana, C. brassicicola (infecting Brassica, e.g., cabbage, rape), C. canescens (infecting e.g., soybean, tomato), C. carotae (infecting carrots), C. chenopodii, C. cistineareum, C. cladosporioides , C. diazu, C. erysimi, C. hayli, C. kikuchii (infecting soybean), C. longpipes (infecting sugarcane), C. malvicola, C. medicaginus (infecting trifolium), C. nicotianae (infecting tobacco), C. oryzae (infecting rice), C. per sonata, C. plantaginis, C. ricinella, C. setariae, C. unamunoi, C. violae, and C. zea-maydis (infecting corn). Methods are readily available in the art for the hybridization of nucleic acid sequences. Sequences that code for photosensitizers from a broad range of species may be isolated according to well known techniques based on their sequence homology to the coding sequences (e.g., sorl) set forth herein. In these techniques, all or part of the known coding sequence is used as a probe which selectively hybridizes to other photosensitizer resistance coding sequences present in a population of cloned genomic DNA fragments or cDNA fragments (i.e. genomic or cDNA libraries) from a chosen organism. For example, the entire sequence provided as SEQ ID NO:l, or portions thereof may be used as probes capable of specifically hybridizing to corresponding coding sequences and messenger RNAs. To achieve specific hybridization under a variety of conditions, such probes include sequences that are unique among coding sequences that encode resistance to photosensitizers {hereinafter resistance coding sequences), and are preferably at least about 10 nucleotides in length, and most preferably at least about 20 nucleotides in length. Such probes may be used to amplify resistance coding sequences from a chosen organism by the well-know process of polymerase chain reaction (PCR). This technique may be used to isolate additional resistance coding sequences from a desired organism or as a diagnostic assay to determine the presence of resistance coding sequences in an organism. Such techniques include hybridization screening of plated DNA libraries (either plaques or colonies; see, e.g.. Sambrook et al. , Molecular Cloning, eds., Cold Spring Harbor Laboratory Press (1989)) and amplification by PCR using oligonucleotide primers corresponding to sequence domains conserved among the amino acid sequences (see, e.g. Innis et al. , PCR Protocols, a Guide to Methods and Applications , eds. , Academic Press (1990)). For example, hybridization of such sequences may be carried out under conditions of reduced stringency, medium stringency or even stringent conditions (e.g., conditions represented by a wash stringency of 35-40% Formamide with 5x Denhardt's solution, 0.5% SDS and lx SSPE at 37° C; conditions represented by a wash stringency of 40-45 % Formamide with 5x Denhardt's solution, 0.5% SDS, and lx SSPE at 42°C; and conditions represented by a wash stringency of 50% Formamide with 5x Denhardt's solution, 0.5% SDS and lx SSPE at 42°C, respectively), to DNA encoding resistance to photosensitizers disclosed herein in a standard hybridization assay. See J. Sambrook et al. , Molecular Cloning, A Laboratory Manual 2d Ed. (1989) Cold Spring Harbor Laboratory. In general, sequences which code for a photosensitizer resistance protein and hybridize to the C. nicotianae gene disclosed herein as SEQ ID NO:l will be at least 50% homologous, 70% homologous, and even 85 % homologous or more with the C. nicotianae sequence. That is, the sequence similarity of sequences may range, sharing at least about 50% , about 70% , and even about 85% , 90% , 95% or more sequence similarity. Also provided are mutant forms of the C. nicotianae photosensitizer resistance gene, and the proteins they encode. Methods for mutagenesis and nucleotide sequence alterations are well known in the art. See, for example, Kunkel, T. (1985) Proc. Natl. Acad. Sci. USA §2:488-492; Kunkel et al. (1987) Methods in Enzymol. 154:361-382; US Patent No. 4,873,192; Walker and Gaastra (eds.) Techniques in Molecular Biology, MacMillan Publishing Company, NY (1983) and the references cited therein. Thus, the genes and nucleotide sequences of the invention include both the naturally occurring sequences as well as mutant forms. Likewise, the proteins of the invention encompass both naturally occurring proteins as well as variations and modified forms thereof. The nucleotide sequences encoding the proteins or polypeptides of the invention are useful in the genetic manipulation of organisms, including bacteria, fungi, plants and animals. This aspect of the invention is illustrated herein with respect to the genetic manipulation of plants. In this manner, the nucleotide sequences of the present invention are provided in expression cassettes for expression in the plant of interest. The cassette will include 5' and 3' regulatory sequences operably linked to the gene of interest. The term "operably linked, " as used herein, refers to DNA sequences on a single DNA molecule which are associated so that the function of one is affected by the other. Thus, a promoter is operatively associated with a gene of the present invention when it is capable of affecting the expression of the gene of the present invention (i.e., the gene is under the transcriptional control of the promoter). The promoter is said to be "upstream" from the gene, which is in turn said to be "downstream" from the promoter. Expression cassettes of the present invention include, 5 '-3' in the direction of transcription, a promoter as discussed above, a gene of the present invention operatively associated with the promoter, and, optionally, a termination sequence including stop signal for RNA polymerase and a polyadenylation signal for polyadenylase (e.g. , the nos terminator). All of these regulatory regions should be capable of operating in the cells of the tissue to be transformed. The 3' termination region may be derived from the same gene as the transcriptional initiation region or may be derived from a different gene. The cassette may additionally contain at least one additional gene to be cotransformed into the organism. Alternatively, the gene(s) of interest can be provided on another expression cassette. Where appropriate, the gene(s) may be optimized for increased expression in the transformed plant. The expression cassettes may additionally contain 5 ' leader sequences in the expression cassette construct. Such leader sequences can act to enhance translation. Translation leaders are known in the art and include: picornavirus leaders, for example, EMCV leader (Encephalomyocarditis 5' noncoding region) (Elroy-Stein, O. , Fuerst, T.R., and Moss, B. (1989) PNAS USA, §6:6126-6130); poty virus leaders, for example, TEV leader (Tobacco Etch Virus) (Allison et al. (1986); MDMV leader (Maize Dwarf Mosaic Virus); Virology, 154:9-20), and human immunoglobulin heavy-chain binding protein (BiP), (Macejak, D.G., and P. Sarnow (1991) Nature, 553:90-94; untranslated leader from the coat protein mRNA of alfalfa mosaic virus (AMV RNA 4), (Jobling, S.A. , and Gehrke, L. , (1987) Nature, 325:622-625; tobacco mosaic virus leader (TMV), (Gallie, D.R. et al. (1989) Molecular Biology of RNA, pages 237-256; and maize chlorotic mottle virus leader (MCMV) (Lommel, S.A. et al. (1991) Virology, §7:382-385). See also, Della-Cioppa et al. (1987) Plant Physiology, §4:965-968. Other methods known to enhance translation can also be utilized, for example, introns, and the like. In preparing the expression cassette, the various DNA fragments may be manipulated, so as to provide for the DNA sequences in the proper orientation and, as appropriate, in the proper reading frame. Towards this end, adapters or linkers may be employed to join the DNA fragments or other manipulations may be involved to provide for convenient restriction sites, removal of superfluous DNA, removal of restriction sites, or the like. For this purpose, in vitro mutagenesis, primer repair, restriction, annealing, resection, ligation, PCR, or the like may be employed, where insertions, deletions or substitutions, e.g. transitions and transversions, may be involved. The compositions and methods of the present invention can be used to transform any plant, or any portion of a plant thereof. In this manner, genetically modified plants, plant cells, plant tissue (e.g., plant leaves, stems, roots), seeds, seed coats, and the like can be obtained. Transformation protocols may vary depending on the type of plant or plant cell, i.e. monocot or dicot, targeted for transformation. Suitable methods of transforming plant cells include microinjection (Crossway et al. (1986) Bio techniques 4:320-334), electroporation (Riggs et al. (1986) Proc. Natl. Acad. Sci. USA, 83: 5602-5606, Agrobacterium mediated transformation (Hinchee et al. (1988) Biotechnology, 6:915-921), direct gene transfer (Paszkowski et al. (1984) EMBO J., 5:2717-2722), and ballistic particle acceleration (see, for example, Sanford et al , U.S. Patent 4,945,050; WO91/10725 and McCabe et al. (1988) Biotechnology, 6:923-926). Also see, Weissinger et al. (1988) Annual Rev. Genet., 22:421-477; Sanford et al. (1987) Particulate Science and Technology, 5:21-31 (onion); Christou et al. (1988) Plant Physiol. §7:671-674(soybean); McCabe et al. (1988) Bio /Technology, 6:923-926 (soybean); Datta et al. (1990) Biotechnology, §:736-740(rice); Klein et al. (1988) Proc. Natl. Acad. Sci. USA, §5:4305-4309(maize); Klein et al. (1988) Biotechnology, 6:559-563 (maize); WO91/10725 (maize); Klein et al. (1988) Plant Physiol, 97:440-444(maize); Fromm et al. (1990) Biotechnology, §:833-839; and Gordon-Kamm et al. (1990) Plant Cell, 2:603-618 (maize); Hooydaas-Van Slogteren & Hooykaas (1984) Nature (London), 311:163-164; Bytebier et al. (1987) Proc. Natl. Acad. Sci. USA, §4:5345-5349 (Liliaceae); De Wet et al. (1985) In 77ze Experimental Manipulation of Ovule Tissues, ed. G.P. Chapman et al. , pp. 197- 209. Longman, NY (pollen); Kaeppler et al. (1990) Plant Cell Reports, 9:415-418; and Kaeppler et al. (1992) Theor. Appl. Genet., §4:560-566 (whisker-mediated transformation); D Halluinet al. (1992) Plant Cell, 4: 1495-1505 (electroporation); Li et al. (1993) Plant Cell Reports, 72:250-255 and Christou and Ford (1995) Annals of Botany, 75:407-413 (rice); Osjoda et al. (1996) Nature Biotechnology, 74:745-750 (maize via Agrobacterium tumefaciens); all of which are herein incorporated by reference. Plant species may be transformed with the DNA construct of the present invention by the DNA-mediated transformation of plant cell protoplasts and subsequent regeneration of the plant from the transformed protoplasts in accordance with procedures well known in the art. Any plant tissue capable of subsequent clonal propagation, whether by organogenesis or embryogenesis, may be transformed with a vector of the present invention. The term "organogenesis, " as used herein, means a process by which shoots and roots are developed sequentially from meristematic centers; the term "embryogenesis," as used herein, means a process by which shoots and roots develop together in a concerted fashion (not sequentially), whether from somatic cells or gametes. The particular tissue chosen will vary depending on the clonal propagation systems available for, and best suited to, the particular species being transformed. Exemplary tissue targets include leaf disks, pollen, embryos, cotyledons, hypocotyls, megagametophytes, callus tissue, existing meristematic tissue (e.g., apical meristems, axillary buds, and root meristems), and induced meristem tissue (e.g., cotyledon meristem and hypocotyl meristem). Plants of the present invention may take a variety of forms. The plants may be chimeras of transformed cells and non-transformed cells; the plants may be clonal transformants (e.g. , all cells transformed to contain the expression cassette); the plants may comprise grafts of transformed and untransformed tissues (e.g., a transformed root stock grafted to an untransformed scion in citrus species). Plants which may be employed in practicing the present invention include (but are not limited to) tobacco (Nicotiana tabacum), potato (Solanum tuberosum), soybean (glycine max), peanuts (Arachis hypogaea), Brassica species (e.g. , rape, canola), sorghum (Sorghum bicolor), cotton (Gossypium hirsutum), sweet potato (Ipomoea batatus), cassava (Manihot esculenta), coffee (Cofea spp.), coconut (Cocos nucifera), pineapple (Ananas comosus), citrus trees (Citrus spp.), cocoa (Theobroma cacao), tea (Camellia sinensis), banana (Musa spp.), avocado (Per sea americana), fig (Ficus casica), guava (Psidium guajava), mango (Mangifera indica), olive (Olea europaea), papaya (Carica papaya), Cashew (Anacardium occidentale), macadamia (Macadamia integrifolia), almond (Prunus amygdalus), sugar beets (Beta vulgaris), corn (Zea mays), wheat, oats, rye, barley, rice, vegetables, ornamentals, and conifers. Vegetables include tomatoes (Lycopersicon esculentum), carrots, asparagus, lettuce (e.g. , Lactuea sativa), green beans (Phaseolus vulgaris), lima beans (Phaseolus limensis), peas (Lathy rus spp.) and members of the genus Cucumis such as cucumber (C. sativus), cantaloupe (C. cantalupensis) , and musk melon (C. melo). Ornamentals include azalea (Rhododendron spp.), hydrangea (Macrophylla hydrangea), hibiscus (Hibiscus rosasanensis) , roses (Rosa spp.), tulips (Tulipa spp.), daffodils (Narcissus spp.), petnunias (Petunia hybrida), carnation (dianthus caryophyllus) , poinsettia (Euphorbia pulchenma) , and chyrsanthemum. Conifers which may be employed in practicing the present invention include, for example, pines such as loblolly pine (Pinus taeda), slash pine (Pinus elliotiϊ), ponderosa pine (Pinus ponderosa), lodgepole pine (Pinus contorta), and Monterey pine (Pinus radiata); Douglas-fir (Pseudotsuga menziesii); Western hemlock (Tsuga canadensis); Sitka spruce (Picea glauca); redwood (Sequoia sempervirens); true firs such as silver fir (Abies amabilis) and balsam fir (Abies balsamea); and cedars such as Western red cedar (Thuja plicata) and Alaska yellow-cedar (Chamaecyparis nootkatensis) . The cells which have been transformed may be grown into plants in accordance with conventional ways. See, for example, McCormick et al. (1986) Plant Cell Reports, 5:81-84. These plants may then be grown, and either pollinated with the same transformed strain or different strains, and the resulting hybrid having the desired phenotypic characteristic identified. Two or more generations may be grown to ensure that the subject phenotypic characteristic is stably maintained and inherited and then seeds harvested to ensure the desired phenotype or other property has been achieved. When a gene encoding resistance to a photosensitizers is included in an expression cassette, the gene may be used in combination with a marker gene, which may be useful in one or more hosts, or different markers for individual hosts. That is, one marker may be employed for selection in a prokaryotic host, while another marker may be employed for selection in a eukaryotic host, particularly the plant host. The markers may be protection against a biocide, such as antibiotics, toxins, heavy metals, or the like; provide complementation, by imparting prototrophy to an auxotrophic host: or provide a visible phenotype through the production of a novel compound in the plant. Exemplary genes which may be employed include neomycin phosphotransferase (NPTII), hygromycin phosphotransferase (HPT), chloramphenicol acetyltransferase (CAT), nitrilase, and the gentamicin resistance gene. For plant host selection, non-limiting examples of suitable markers are beta-glucuronidase, providing indigo production, luciferase, providing visible light production, NPTII, providing kanamycin resistance or G418 resistance, HPT, providing hygromycin resistance, and the mutated aroA gene, providing glyphosate resistance. Selectable marker genes and reporter genes are known in the art. See generally, G. T. Yarranton (1992) Curr. Opin. Biotech., 3:506-511; Christopherson et al. (1992) Proc. Natl. Acad. Sci. USA, §9:6314-6318; Yao et al. (1992) Cell, 77:63-72; W. S. Reznikoff (1992) Mol. Microbiol., 6:2419- 2422; Barkley et al. (1980) The Operon, pp. 177-220; Hu et al. (1987) Cell, 4§:555-566; Brown et al. (1987) Cell, 49:603-612; Figge et al. (1988) Cell, 52:713-722; and, Deuschle et al. (1989) Proc. Natl. Acad. Aci. USA, §6:5400- 5404. Other genes of interest may additionally be included. The respective genes may be contained in a single expression cassette, or alternatively in separate cassettes. Methods for construction of the cassettes and transformation methods have been described above. As discussed, the genes of the invention can be manipulated to enhance disease resistance in plants. In this manner, the expression or activity of the gene encoding resistance to photosensitizers is altered. Such means for alteration of the gene include co-suppression, antisense, mutagenesis, alteration of the sub-cellular localization of the protein, etc. In some instances, it may be beneficial to express the gene from an inducible promoter, particularly from a pathogen inducible promoter. Such promoters include those from pathogenesis- related proteins (PR proteins) which are induced following infection by a pathogen; e.g., PR proteins, SAR proteins, beta-l,3-glucanase, chitinase, etc. See, for example, Redolfi et al. (1983) Neth. J. Plant Pathol. §9:245-254; Uknes et al. (1992) The Plant Cell 4:645-656; and Van Loon (1985) Plant Mol. Virol. 4: 111- 116. Nucleotide sequences of the present invention are also useful as selectable markers in transforming plant or fungal cells. A pyridoxine-deficient Aspergillus flavus transformed with SOR1 was found to be able to grow on minimal media lacking pyridoxine. Accordingly, the S0R7 gene may be used as a marker gene in combination with a second gene, where it is desired to transform plants with the second gene. Successful transformation is indicated by the ability of the transformant to grow on media lacking pyridoxine, where the original (untransformed) plant is unable to grow. Methods and constructs for selectable marker use are well-known in the art. Using the present nucleotide sequences in methods of selecting, from a plurality of cells that have undergone a transformation procedure, only those cells that have been successfully transformed, would comprise transforming cells from an organism that is unable to grow (or grows poorly) in the absence of exogenous pyridoxine (for example, in medium that does not contain pyridoxine). Numerous suitable transformation procedures are known in the art; the selection of a suitable procedure would depend on the cells being transformed and the desired effect. Selection of suitable transformation procedures will be apparent to those skilled in the art. The cells are subjected to a transformation procedure using a construct comprising a heterologous DNA sequence of interest and a second DNA sequence according to the present invention, such as SEQ ID NO:l or the open reading frame thereof. The cells are then placed on medium lacking pyridoxine; only those cells that are able to grow on the medium have been successfully transformed. The present invention is more fully illustrated by the following Examples, which are set forth to illustrate the present invention and are not to be construed as limiting thereof. Example 1 Isolation of Cercosporin-Sensitive Mutants Mutants of Cercospora nicotianae which are sensitive to cercosporin are isolated according to procedures described in A. E. Jenns et al. , Photochem. Photobiol. 61, 488-493 (1995) and A. E. Jenns and M. E. Daub, Phytopathol. 85, 96-912 (1995). The mutants are isolated from UV-mutagenized mycelial protoplasts, and screened for cercosporin sensitivity by replica-plating colonies on cercosporin-containing medium. All isolation and screening is done under conditions that suppress endogenous cercosporin synthesis (A. E. Jenns et al. , Phytopathol. 19, 213-219 (1989). Six cercosporin-sensitive (CS) mutants are isolated, and are characterized into two phenotypic classes. Five of the mutants (CS2, CS6, CS7, CS8, and CS9, designated class 1) are totally inhibited when grown on medium containing cercosporin at concentrations as low as 1 μM. The sixth mutant (CS10, designated class 2), is partially inhibited by 10 uM cercosporin, but not at lower concentrations. When the mutants are assayed by fluorescence microscopy, the class 1 mutants are found to be incapable of reducing cercosporin. The partially-sensitive CS10, however, is normal in cercosporin-reducing ability. Further phenotypic characterization is done according to the method of Jenns and Daub, supra. All of the mutants are capable of synthesizing cercosporin when grown under conditions that induce cercosporin synthesis. The class 1 mutants stop growing when cercosporin is produced, but, surprisingly, endogenous cercosporin production appears to have little effect on growth of CS10. Cercosporin sensitivity is not due to a general sensitivity of any of the mutants to light. As with other sensitive fungi, the mutants are able to be protected against cercosporin toxicity by the addition of reducing agents such as ascorbate, cysteine, and reduced glutathione. However, none of the mutants is altered in production of these compounds or in levels of total soluble or protein thiols, indicating that resistance is not due to endogenous production of these agents. The mutants are also tested for resistance to five other singlet oxygen-generating photosensitizers: methylene blue, toluidine blue, rose bengal, eosin Y, and hematoporphyrin. Wild type C. nicotianae is highly resistant to all these photosensitizers, with the exception of rose bengal, which shows some toxicity to these fungi. Surprisingly, the class 1 sensitive mutants were completely inhibited by all of the photosensitizers. This level of sensitivity was unexpected, as even the most cercosporin-sensitive, naturally-occurring fungal species are capable of at least some growth on these compounds. Thus the class 1 mutants appear to be mutant in a gene which mediates resistance to a range of singlet oxygen-generating photosensitizers, and such a mutation results in levels of photosensitizer sensitivity not occurring in fungi in nature. In contrast, the sensitivity of mutant CS10 was specific to cercosporin; response of CS10 to the other photosensitizers was identical to that of wild type. Example 2 Isolation of genes encoding resistance to cercosporin A genomic library is constructed from the C. nicotianae wild type strain (ATCC# 18366) in a bialaphos-resistance-conferring plasmid, pBAR3 (Straubinger et al., Fungal Genetics Newsletter 39, 82-83 (1992), which is modified by addition of a COS site to allow the cloning of inserts of approximately 45 kb. Approximately 4,000 cosmid clones are isolated and stored individually in wells of microtitre plates. Estimating the size of the C. nicotianae haploid genome as equal to that of N. crassa (4 X 10 7 ), the library is estimated to have a 99% probability of representing the entire genome as intact fragments. DΝA for transformation is prepared by growing each cosmid clone separately as 5 ml cultures and then pooling all cultures from one microtitre plate. Pooled DΝA is then transformed into both CS10 and CS8. CS10 was chosen as it is the only mutant characterized by being partially cercosporin sensitive, unaffected in cercosporin reduction, and unaffected by other photosensitizers. CS8 is representative of the five class 1 mutants which are totally sensitive to both cercosporin and other photosensitizers and are unable to reduce cercosporin. CS8 was chosen since it grows well in the absence of cercosporin, sporulates well, and is the most easily transformed of the class 1 mutants. Transformants are selected for resistance to bialaphos, and then 300-400 transformants resulting from transformation with each plate of DNA are screened for resistance to cercosporin by growing them on medium containing 10 uM cercosporin. Clones complementing both mutations are identified. Four colonies showing wild-type levels of resistance are recovered from the partially cercosporin-sensitive CS10 transformed with DNA from one selected plate. Transformation of CS10 with DNA from individual clones of this plate resulted in the identification of a specific complementing cosmid clone, designated 30H2. Forty-two percent of CS10 colonies transformed with clone 30H2 exhibit a cercosporin resistance phenotype indistinguishable from that of the wild type. Eleven CS8 colonies resulting from transformation with DNA from another selected exhibit wild- type levels of cercosporin resistance. A specific complementing cosmid clone, designated 18E1, is identified. Seventy-eight percent of CS8 colonies transformed with clone 18E1 show wild type levels of cercosporin resistance. Clone 18E1 also restores wild-type levels of resistance in CS8 to the five other singlet oxygen-generating photosensitizers, toluidine blue, methylene blue, eosin Y, hematoporphyrin and rose bengal. As all the class 1 mutants (CS2, CS6, CS7, CS8, and CS9) share an identical phenotype. The phenotype of the class 1 mutants suggests that the resistance gene complementing them imparts resistance to '0 2 specifically. Because of the differences in phenotype between CS10 and the class 1 mutants, it is thought that the mutations are in different loci. This hypothesis is supported by transformation experiments. Transformation of CS8 with clone 30H2 failed to restore any level of resistance to cercosporin. Similarly, clone 18E1 did not complement CS10. Example 3 Sequence analysis of genes encoding resistance to cercosporin Since the cosmids which complement CS8 and CS10 each contain more than 40 kb of C. nicotianae DNA, overlapping restriction fragments were subcloned to identify shorter sequences of DNA (5-10 kb) which confer cercosporin resistance. Complementing subclones from each cosmid were mapped, and a common restriction fragment used as a probe in northern analysis to determine that they hybridize to a single message. These probes were then used to identify full length cDNAs corresponding to the genes from 18E1 and 30H2 which confer resistance to photosensitizers. Both the genomic fragments and the cDNAs are sequenced. The technique of primer-walking is used to generate nested deletions for sequencing, using an approach used previously to sequence the C. nicotianae phytoene dehydrogenase gene (M. Ehrenshaft and M.E. Daub, Appl. Environ. Microbiol. 60, 2166-211 \ (1994)). Deletion clones are sequenced at the University of Georgia Molecular Genetics Facility (Athens, Georgia, USA). A gene located within clone 18E1 that confers cercosporin resistance (the gene is named sorl) to C. nicotianae was sequenced. The sequence analysis of sorl revealed an open reading frame encoding a protein of 343 amino acid residues. The nucleotide sequence of the gene, in the 5' to 3' direction is given herein as SEQ ID NO:l (see Figure 1). The open reading frame of SEQ ID NO:l is nucleotides 825-1853, inclusive. The predicted amino acid sequence of the protein expressed by the isolated sorl gene encoding cercosporin resistance is (in the NH 2 -terminal to COOH-terminal) direction: MASNGTSVSP FSQKNAAMA VNDTPANGHA EPSTITAASK TNTTKITSQN DPQSSFAVKV GLAQMLKGGV IMDVVNAEQA RIAEEAGACA VMALERVPAD IRKDGGVARM SDPQMIKDIM NAVTIPVMAK SRIGHFVECQ ILQAIGVDYI DESEVLTPAD PVNHIDKSVY NVPFVCGCKN LGEALRRISE GAAMIRTKGE AGTGDVVEAV RHMQTVNAEI AKASSASDAD LRMMARELQC DYNLLKQTAQ L RLPVVNFA AGGIATPADA ALMQMGCDG VFVGSGIFKS GDAAKRAKAI VQATTHYNDP KVLAEVSSGL GEAMVGINCD KLPETQKLAT RGW (SEQ ID N0:2) Example 3A A gene located within clone 30H2 that also confers cercosporin resistance (the gene is named crgl) to C. nicotianae was sequenced; the nucleotide sequence of the gene, in the 5' to 3' direction is provided herein as SEQ ID NO:9. The sequence analysis of crgl revealed an open reading frame (nucleotides 742- 2391, inclusive, of SEQ ID NO:9) encoding a protein of 550 amino acid residues. The predicted amino acid sequence of the protein expressed by the isolated crgl gene encoding cercosporin resistance is (in the NH 2 -terminal to COOH-terminal direction) provided in SEQ ID NO: 10. Example 4 Confirmation of Identity of Gene Encoding Resistance to Cercosporin Mutant Cercospora that lacked the SOR1 gene (null mutants) have been produced. These mutants are sensitive to cercosporin and to other photosensitizers, as were the original mutants, thus confirming the function of SOR7. After identification of the specific cercosporin resistance genes via mapping and sequencing of cDNA and genomic clones, complementing genes were used in gene disruption experiments in order to definitively confirm their identity. This approach was previously used to create carotenoid-minus mutants in C. nicotianae (Ehrenshaft et al., Molec. Plant. Microb. Interact. 8, 569-575 (1995)). Wild type C. nicotianae strain ATCC #18366 was transformed with a disrupted version of the SOR1 resistance genes. Southern analysis identified both transformants in which the disrupted gene replaced the wild-type copy, and transformants which contained both a wild-type and a disrupted version. Transformants were screened for loss or decrease in cercosporin resistance, and loss or decrease in resistance to the other singlet-oxygen-generating photosensitizers described above in Jenns et al. (1995), supra, and Ehrenshaft et al. , (1995), supra. The null mutants created by the above methods were completely sensitive to cercosporin and to other photosensitizers. These results confirm that SOR7 functions to provide resistance to cercosporin and other singlet- oxygen-generating photosensitizers . The same methods as described above are used to confirm the function of the CRG1 gene. Example 5 Expression of resistance genes in Aspergillus flavus The phenotype of the class 1 mutants suggests that the resistance gene complementing imparts resistance to singlet oxygen. If so, this gene (with or without the CS10 complementing gene) may be useful in genetic engineering of other organisms for photosensitizer or singlet oxygen resistance. The ability of the CS8 and CS 10 complementing genes (individually and together) to impart resistance in heterologous organisms is tested using cercosporin-sensitive fungus A. flavus. The cercosporin-resistance gene of the present invention is thus expressed in A. flavus. This fungus is used to test expression of the gene of the present invention because it is highly sensitive to cercosporin. M.E. Daub et al. , Proc. Natl. Acad. Sci USA 89, 9588-9592 (1992). The A. flavus strain 656-2, generously provided by Dr. Gary Payne (Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina) is transformed with the gene according to the method of CP. Woloshuk et al. , Appl. Environ. Microbiol. 55, 86- 90 (1989). Briefly, protoplasts are isolated from the A. flavus strain 656-2, a uridine-requiring mutant, by incubating mycelium with an enzyme solution (10 mM NaPO 4 , pH 5.8, 20 mM CaCl 2 , 105 u/mL β-glucorinidase, Novozym 234, 1.2 M NaCl). The cercosporin-resistance gene sorl is cloned into the plasmid pUC19pyr4. The plasmid contains the Neurospora crassa gene pyr4, which restores the ability to grow without uridine. Protoplasts are mixed with plasmid DNA, plated onto a regenerating medium (MLS) lacking uridine. Transformants that grow on these plates are then inoculated onto potato dextrose agar containing μM cercosporin and inoculated in the light, and colony diameter measured at three days. Alternatively, the sorl open reading frame is cloned into the plasmid pBargpel downstream from the promoter of the Aspergillus gpdA gene. The promoter expresses constitutively in A. flavus. As a marker for transformation into C. nicotianae, the plasmid contains the bar gene, which encodes resistance to bialaphos. The plasmid is transformed into the mutant CS8 described above, and is shown to complement the cercosporin-sensitive mutation. The pyr4 gene, as described above, is then cloned into the plasmid construct in order to provide a marker for transformation into the Aspergillus strain 656-2. Transformants that exhibit resistance to cercosporin are then detected as described above. Example 5A Expression of resistance genes in Aspergillus flavus SORl was expressed in Aspergillus flavus according to the methods of Example 5 (expressing the SORl ORF downstream from the gpdA promoter). Data provided in Table 1 regarding gpdA: SORl transformants and three control colonies transformed only with vector, indicate that resistance of A. flavus to cercosporin can be improved by transformation with the S07?7 gene construct. A growth effect was also observed; the SORl transformants grew better in the absence of cercosporin. This effect may be due to the ability of SORl to complement a pyridoxine mutation. The particular A. flavus strain utilized was a pyridoxine mutant, however, all colonies were grown on complex media that contained pyridoxine. Table 1 Growth of A. flavus gpdA.SORl transformants Example 6 Isolation of sorl homologue in Alternaria alternata Using the C. nicotianae sorl gene as a probe, a genomic library of the fungus Alternaria alternata was probed under conditions of lowered stringency, as defined above. A full-length A. alternata gene homologous to the C. nicotianae sorl gene was isolated, and the gene sequenced according to known techniques (SEQ ID NO: 10). A partial (310 base pairs) DNA sequence of the A. alternata gene is provided in FIGURE 3A (SEQ ID NO:3); the predicted amino acid sequence, corresponding to the C-terminus of the protein encoded by the nucleic acid sequence, is provided in FIGURE 3B (SEQ ID NO:4). The partial DNA sequence of the A. alternata gene is shown aligned with the corresponding segment of the C. nicotianae sorl gene (SEQ ID NO:5) in FIGURE 4A. In FIG. 4A, the " = " sign indicates that aligned residues are identical. Aligning the complete DNA sequences of the A. alternata gene (SEQ ID NO:10) and the C. nicotianae sorl gene (SEQ ID NO:l) in a similar matter (not shown) indicates sequence identity of 78.2% . The predicted C-terminus amino acid sequence of both genes is shown aligned in FIGURE 4B (SEQ ID NO:6 (A. alternata) and SEQ ID NO:7 (SORl)); the complete amino acid sequence of each gene (SEQ ID NO:2 and SEQ ID NO:ll) is shown aligned in FIGURE 4C. In FIG. 4B and 4C, the " = " sign indicates that aligned residues are identical, while the "-" sign indicates that the aligned residues are similar. "Similar" residues are as follows: A, S, and T are deemed similar to each other; D and E are similar; N and Q are similar; R and K are similar; I, L, M and V are similar; and F, Y and W are similar. The complete nucleotide sequence of the A. alternata homolog of SORl was sequenced (SEQ ID NO:10); the complete predicted amino acid sequence of the A. alternata homolog is provided in SEQ ID NO:ll. Example 7 Determination of homology to other known genes and gene products Protein sequences derived from the nucleotide sequence were analyzed for homology to other protein sequences using the National Center for Biotechnology Institute BLAST network service. S.F. Altshul et al. J. Mol. Biol. 215, 403-410 (1990)). The data base search revealed several protein sequences with 55-75 % homology to the predicted polypeptide of SEQ ID NO:2, in organisms from divergent kingdoms, as shown in TABLE 2. There are no defined functions associated with any of the identified homologs. A yeast homologs encodes a protein that has been reported to increase in stationary phase; it has been suggested that this protein is a cell arrest protein (Braun et al., J. Bacteriol. 178:6865 (1996)). The gene from Hevea is up-regulated in the presence of ethylene and salicylic acid (Sivasubramaniam et al. , Plant Mol. Biol. 29: 173 (1995)). Table 2 Presence of Homologues to SORl * complete = entire genome sequenced; not complete = genome sequencing underway but not complete; est = expressed sequence tags. Organisms from the kingdom Eubacteria that lack SORl homologues have also been identified: Escherichia coli; Synechocysits; Helicobacter pylori; Borrelia burgdoferi; Mycoplasma pneumoniae; Mycoplasma genitalium. The complete genome has been sequenced for each of these organisms. Many modifications and other embodiments of the invention will come to mind in one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated Figures. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed. Although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. Modifications and alternative embodiments of the present invention are intended to be included within the scope of the appended claims. Example 8 Use of SORl as a Selectable Marker SORl mutants were found to be unable to grow on minimal medium, but able to grow when the minimal medium was supplemented with pyridoxine. SORl does not show significant sequence similarity to any of the genes currently identified as acting in the pyridoxine biosynthetic pathway. SORl mutants were sensitive to cercosporin even when grown on medium containing pyridoxine, indicating that pyridoxine is not required for cercosporin resistance. A pyridoxine-deficient mutant of Aspergillus flavus (ATCC# 60045) was transformed using the protocol described in Example 5, above. Example 5 describes transformation and selection using the pyr4 gene, and selecting transformants based on the ability to grow without uridine. In the present experiment, protoplasts were transformed with constructs containing the S R7 ORF under the control of the Aspergillus nidulans glyceraldehyde-3 -phosphate dehydrogenase gene (gpdA promoter). The gpdA promoter is known to provide high, constitutive expression in A. flavus. Transformants were selected on minimal medium that lacked pyridoxine. Non-transformed protoplasts and protoplasts transformed with the vector plasmid lacking SORl did not grow; transformants expressing SORl grew. Transformation frequency appeared to be similar to that obtained with the pyr4 marker, although side-by-side comparisons have not been completed. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: Daub, Margaret E. Ehrenshaft, Marilyn Jenns , Ann E . (ii) TITLE OF INVENTION: Isolated Genes and Proteins Encoding Resistance to Photosensitizers (iii) NUMBER OF SEQUENCES: 11 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Virginia C. Bennett (B) STREET: PO Box 37428 (C) CITY: Raleigh (D) STATE: North Carolina (E) COUNTRY: US (F) ZIP: 27627 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: PatentIn Release #1.0, Version #1.30 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: (B) FILING DATE: (C) CLASSIFICATION: (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: Bennett, Virginia C. (B) REGISTRATION NUMBER: 37,092 (C) REFERENCE/DOCKET NUMBER: 5405.333 (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: 919-854-1400 (B) TELEFAX: 919-854-1401 (2) INFORMATION FOR SEQ ID NO : 1 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2010 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS : single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 825..1853 (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 1 : GGATCCAAAA TTGGGCCATG TTGTGCAGAG TGCGGTCTGG GAGGGTAGAG TGTTTTCGGT 60 GTCAAGCTTC ACTCACGCAG GAGGTCAAAG TCTACACAGA AGACCTCATC GAGCAGCTGA 120 GCTCTCTTAT TGCGATTACA GCTCAGCACT CGGCCGAGGA ACGCGTGGAT TCCTGGTTCC 180 CCTCATGGGC ATTGTAGCTT CAGCAGACTC GTCCGCCGCG ACTCTGCTCG CGTATGAGTA 240 GCTCGTGCTG ACCAGCAATC GCGGAGCTGA GCTGCAGTGC TCGCATCGCA GTCACAGAAG 300 GATGACCACC GTCTTGTAGC GCGGCGCACG CGGGCCAGCA CCTGAGGTCG GAGGGTTGGC 360 ACATGGACGG ACGAGCTGGT GGTTGTCACA TGCCGGCTCA GTCGCGGCAC TCAGCAGGCA 420 GGGAAGGCGC CGTCGGACCC TGCAGCACGT CTCGGCTCCT TGGCCGAAGC ACGATCTTCC 480 CCGCGATCGC AGGCGCAAAT GACTCTTCGA ACATTTTCTC GCCGCATCTG GCCGCTGTCA 540 GAGGCAAGTC TCGCACCGTG TCGCGCCCTA CCAGACACAA GCACCCTCCT GTTCCAGTGC 600 TCGCCAAAGC ATTGCCGCAT CGAGCTTCCT TTCGCGACCA TTGCCTGCCC TCCGAGCCCA 660 GCATATAGAC TTTCCTAGTT CCGCCGATTT TCTTTCCAAG TGCCACCACC TCAATATCGC 720 CTTCGACTTT CTTTCACTGC TGCCCCGCCC TGCATCTGCA CGCCCCACCG CCATTGACCA 780 AATATAACAT CCTCCTACCC TCCGTCTCCA GCACCAGCTA GCAC ATG GCC TCT AAC 836 Met Ala Ser Asn 1 GGA ACT TCT GTA TCA CCT TTC CGA TCT CAA AAG AAC GCC GCA ATG GCT 884 Gly Thr Ser Val Ser Pro Phe Arg Ser Gin Lys Asn Ala Ala Met Ala 5 10 15 20 GTC AAC GAC ACC CCC GCC AAC GGC CAC GCC GAG CCC TCC ACC ATC ACC 932 Val Asn Asp Thr Pro Ala Asn Gly His Ala Glu Pro Ser Thr lie Thr 25 30 35 GCC GCC TCG AAG ACC AAC ACC ACG AAG ATC ACA TCT CAG AAT GAT CCT 980 Ala Ala Ser Lys Thr Asn Thr Thr Lys lie Thr Ser Gin Asn Asp Pro 40 45 50 CAG TCA TCC TTC GCC GTC AAG GTC GGC TTG GCC CAG ATG CTC AAG GGT 1028 Gin Ser Ser Phe Ala Val Lys Val Gly Leu Ala Gin Met Leu Lys Gly 55 60 65 GGC GTG ATC ATG GAT GTG GTC AAC GCA GAG CAA GCA CGC ATT GCT GAA 1076 Gly Val lie Met Asp Val Val Asn Ala Glu Gin Ala Arg He Ala Glu 70 75 80 GAG GCG GGT GCA TGT GCC GTC ATG GCC CTC GAG CGT GTG CCA GCA GAT 1124 Glu Ala Gly Ala Cys Ala Val Met Ala Leu Glu Arg Val Pro Ala Asp 85 90 95 100 ATT CGA AAG GAC GGT GGC GTC GCT CGC ATG AGC GAC CCA CAA ATG ATC 1172 He Arg Lys Asp Gly Gly Val Ala Arg Met Ser Asp Pro Gin Met He 105 110 115 AAG GAC ATC ATG AAT GCT GTG ACC ATC CCT GTC ATG GCG AAG TCG AGG 1220 Lys Asp He Met Asn Ala Val Thr He Pro Val Met Ala Lys Ser Arg 120 125 130 ATT GGT CAC TTC GTG GAA TGT CAG ATT CTC CAA GCC ATT GGC GTG GAC 1268 He Gly His Phe Val Glu Cys Gin He Leu Gin Ala He Gly Val Asp 135 140 145 TAC ATC GAT GAG TCC GAG GTG CTC ACA CCT GCC GAT CCA GTC AAC CAC 1316 Tyr He Asp Glu Ser Glu Val Leu Thr Pro Ala Asp Pro Val Asn His 150 155 160 ATC GAC AAG AGC GTT TAC AAT GTT CCA TTC GTG TGT GGA TGC AAG AAC 1364 He Asp Lys Ser Val Tyr Asn Val Pro Phe Val Cys Gly Cys Lys Asn 165 170 175 180 TTG GGT GAG GCC CTT CGA AGA ATA TCA GAG GGC GCT GCC ATG ATC CGG 1412 Leu Gly Glu Ala Leu Arg Arg He Ser Glu Gly Ala Ala Met He Arg 185 190 195 ACA AAG GGT GAA GCA GGA ACG GGA GAT GTC GTC GAG GCC GTG AGA CAC 1460 Thr Lys Gly Glu Ala Gly Thr Gly Asp Val Val Glu Ala Val Arg His 200 205 210 ATG CAG ACT GTC AAT GCT GAG ATC GCA AAG GCC AGC TCA GCA TCT GAC 1508 Met Gin Thr Val Asn Ala Glu He Ala Lys Ala Ser Ser Ala Ser Asp 215 220 225 GCT GAT CTT CGC ATG ATG GCA CGA GAG CTG CAG TGC GAC TAC AAC CTG 1556 Ala Asp Leu Arg Met Met Ala Arg Glu Leu Gin Cys Asp Tyr Asn Leu 230 235 240 CTC AAG CAG ACC GCA CAG CTC AAG AGA CTG CCA GTG GTC AAC TTC GCT 1604 Leu Lys Gin Thr Ala Gin Leu Lys Arg Leu Pro Val Val Asn Phe Ala 245 250 255 260 GCA GGA GGT ATC GCC ACG CCG GCC GAC GCT GCC TTG ATG ATG CAA ATG 1652 Ala Gly Gly He Ala Thr Pro Ala Asp Ala Ala Leu Met Met Gin Met 265 270 275 GGT TGC GAT GGT GTC TTC GTT GGA TCT GGT ATC TTC AAG TCA GGC GAC 1700 Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe Lys Ser Gly Asp 280 285 290 GCG GCG AAG CGA GCA AAG GCC ATT GTG CAG GCC ACC ACA CAC TAC AAC 1748 Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Thr Thr His Tyr Asn 295 300 305 GAC CCC AAG GTC CTG GCT GAG GTC AGC TCG GGT CTT GGT GAG GCA ATG 1796 Asp Pro Lys Val Leu Ala Glu Val Ser Ser Gly Leu Gly Glu Ala Met 310 315 320 GTG GGC ATC AAC TGC GAC AAG CTG CCA GAG ACA CAG AAG CTG GCG ACC 1844 Val Gly He Asn Cys Asp Lys Leu Pro Glu Thr Gin Lys Leu Ala Thr 325 330 335 340 CGT GGC TGG TAGATGCTGC AAATTCGAAA AAGAAAACGG GAACATGACT 1893 Arg Gly Trp GTAGGCATAG CAGCGGGCGC TTGGGTATGG GTGTGATTGC AATCAAAAGA AAAGCGAGCG 1953 AGTTAGAGAG CACATCTGGG CGTGTTAGAT TCTGTATCGC GCCTCACCGC GCCTAGG 2010 (2) INFORMATION FOR SEQ ID NO : 2 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 343 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 2 : Met Ala Ser Asn Gly Thr Ser Val Ser Pro Phe Arg Ser Gin Lys Asn 1 5 10 15 Ala Ala Met Ala Val Asn Asp Thr Pro Ala Asn Gly His Ala Glu Pro 20 25 30 Ser Thr He Thr Ala Ala Ser Lys Thr Asn Thr Thr Lys He Thr Ser 35 40 45 Gin Asn Asp Pro Gin Ser Ser Phe Ala Val Lys Val Gly Leu Ala Gin 50 55 60 Met Leu Lys Gly Gly Val He Met Asp Val Val Asn Ala Glu Gin Ala 65 70 75 80 Arg He Ala Glu Glu Ala Gly Ala Cys Ala Val Met Ala Leu Glu Arg 85 90 95 Val Pro Ala Asp He Arg Lys Asp Gly Gly Val Ala Arg Met Ser Asp 100 105 110 Pro Gin Met He Lys Asp He Met Asn Ala Val Thr He Pro Val Met 115 120 125 Ala Lys Ser Arg He Gly His Phe Val Glu Cys Gin He Leu Gin Ala 130 135 140 He Gly Val Asp Tyr He Asp Glu Ser Glu Val Leu Thr Pro Ala Asp 145 150 155 160 Pro Val Asn His He Asp Lys Ser Val Tyr Asn Val Pro Phe Val Cys 165 170 175 Gly Cys Lys Asn Leu Gly Glu Ala Leu Arg Arg He Ser Glu Gly Ala 180 185 190 Ala Met He Arg Thr Lys Gly Glu Ala Gly Thr Gly Asp Val Val Glu 195 200 205 Ala Val Arg His Met Gin Thr Val Asn Ala Glu He Ala Lys Ala Ser 210 215 220 Ser Ala Ser Asp Ala Asp Leu Arg Met Met Ala Arg Glu Leu Gin Cys 225 230 235 240 Asp Tyr Asn Leu Leu Lys Gin Thr Ala Gin Leu Lys Arg Leu Pro Val 245 250 255 Val Asn Phe Ala Ala Gly Gly He Ala Thr Pro Ala Asp Ala Ala Leu 260 265 270 Met Met Gin Met Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe 275 280 285 Lys Ser Gly Asp Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Thr 290 295 300 Thr His Tyr Asn Asp Pro Lys Val Leu Ala Glu Val Ser Ser Gly Leu 305 310 315 320 Gly Glu Ala Met Val Gly He Asn Cys Asp Lys Leu Pro Glu Thr Gin 325 330 335 Lys Leu Ala Thr Arg Gly Trp 340 (2) INFORMATION FOR SEQ ID NO : 3 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 310 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS : single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 3 : TATGCGCTGC TCAAGGAGAC GGCTAAGCTT GGTCGTCTGC CTGTTGTCAA CTTTGCGGCG 60 GGTGGTGTCG CAACACCCGC TGATGCTGCG TTGATGATGC AGTTGGGTTG CGATGGTGTC 120 TTTGTTGGTA GCGGTATCTT CAAGTCTGGA GACGCAGCCA AGAGGGCCAA GGCCATCGTA 180 CAGGCTGTTA CTCACTACAA AGACCCCAAG GTGCTCATGG AAGTCAGCAT GGATTTGGGT 240 GAGGCCATGG TTGGTATCAA CTGCGGTACA ATGGGCGAGG AGGAGAAGCT TGCTAAGAGG 300 GGATGGTAGA 310 (2) INFORMATION FOR SEQ ID NO : 4 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 102 amino acids (B) TYPE: amino acid (C) STRANDEDNESS : single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 4 : Tyr Ala Leu Leu Lys Glu Thr Ala Lys Leu Gly Arg Leu Pro Val Val 1 5 10 15 Asn Phe Ala Ala Gly Gly Val Ala Thr Pro Ala Asp Ala Ala Leu Met 20 25 30 Met Gin Leu Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe Lys 35 40 45 Ser Gly Asp Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Val Thr 50 55 60 His Tyr Lys Asp Pro Lys Val Leu Met Glu Val Ser Met Asp Leu Gly 65 70 75 80 Glu Ala Met Val Gly He Asn Cys Gly Thr Met Gly Glu Glu Glu Lys 85 90 95 Leu Ala Lys Arg Gly Trp 100 (2) INFORMATION FOR SEQ ID NO : 5 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 311 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 5 : TACAACCTGC TCAAGCAGAC CGCACAGCTC AAGAGACTGC CAGTGGTCAA CTTCGCTGCA 60 GGAGGTATCG CCACGCCGGC CGACGCTGCC TTGATGATGC AAATGGGTTG CGATGGTGTC 120 TTCGTTGGAT CTGGTATCTT CAAGTCAGGC GACGCGGCGA AGCGAGCAAA GGCCATTGTG 180 CAGGCCACCA CACACTACAA CGACCCCAAG GTCCTGGCTG AGGTCAGCTC GGGTCTTGGT 240 GAGGCAATGG TGGGCATCAA CTGCGACAAG CTGCCAGAGA CACAGAAGCT GGCGACCCGT 300 GGCTGGTAGA T 311 (2) INFORMATION FOR SEQ ID NO : 6 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 100 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 6 : Leu Leu Lys Glu Thr Ala Lys Leu Gly Arg Leu Pro Val Val Asn Phe 1 5 10 15 Ala Ala Gly Gly Val Ala Thr Pro Ala Asp Ala Ala Leu Met Met Gin 20 25 30 Leu Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe Lys Ser Gly 35 40 45 Asp Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Val Thr His Tyr 50 55 60 Lys Asp Pro Lys Val Leu Met Glu Val Ser Met Asp Leu Gly Glu Ala 65 70 75 80 Met Val Gly He Asn Cys Gly Thr Met Gly Glu Glu Glu Lys Leu Ala 85 90 95 Lys Arg Gly Trp 100 (2) INFORMATION FOR SEQ ID NO : 7 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 143 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 7 : Ala Gly Thr Gly Asp Val Val Glu Ala Val Arg His Met Gin Thr Val 1 5 10 15 Asn Ala Glu He Ala Lys Ala Ser Ser Ala Ser Asp Ala Asp Leu Arg 20 25 30 Met Met Ala Arg Glu Leu Gin Cys Asp Tyr Asn Leu Leu Lys Gin Thr 35 40 45 Ala Gin Leu Lys Arg Leu Pro Val Val Asn Phe Ala Ala Gly Gly He 50 55 60 Ala Thr Pro Ala Asp Ala Ala Leu Met Met Gin Met Gly Cys Asp Gly 65 70 75 80 Val Phe Val Gly Ser Gly He Phe Lys Ser Gly Asp Ala Ala Lys Arg 85 90 95 Ala Lys Ala He Val Gin Ala Thr Thr His Tyr Asn Asp Pro Lys Val 100 105 110 Leu Ala Glu Val Ser Ser Gly Leu Gly Glu Ala Met Val Gly He Asn 115 120 125 Cys Asp Lys Leu Pro Glu Thr Gin Lys Leu Ala Thr Arg Gly Trp 130 135 140 (2) INFORMATION FOR SEQ ID NO : 8 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 3420 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 742..2391 (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 8 : GGATCCCCGA TCCAGCGGGA GTATTTGACA TGATTAGGTT CCTTCGGCGA CTACATTGTG 60 AAGTGGTATG CTCGAAGGTC GCATTCCATT GCCATGTCTC TGCAGCGTAG CGTCGAATAC 120 AGCACTTGTT GGGAGAATTG CAGATAGGAG TACAGTCAAC TCAACTTCGA AACAAGTCGT 180 ACTGTACTGC TCAAAGAACC TCAGAGAAAG GTTTCCCACA AGTCTACAGG GATGATTACC 240 GGCATCTGAT TCGCTACCCA ATCGCGCTAT TCCACGTCTG AGCCTTAGCA TCAACTCACC 300 TCTCTCTCAC CCAAGACATT CTGTCACAGC CTCGCGGTGC TTTTTCCGTC ATGCCACATC 360 GCACTTTTCG ACGGCCATGT CACCACGAAT GCCGCAGAAA CGGGGCAGAG CCTGTGAGGC 420 TTGCTCAAAG ATCAAAATCC GGTGCGTGGT CATAACTTCC CGATCAATAG TGGTGCCTGC 480 CACGCGCTGA TGTGATCTGC ATCAAGGTGT TCGCTGGGCC AGGCATCAGA GGATGCAGCA 540 CCGCCTTGCG AGAGATGCGT GCGATTGAAC AAGGAATGCA TTTTGAGCGC TCCAAAGCGT 600 CAGAAAGACC GCGTCGCCGA ACTTGAAGCA CAAGTGGCAC AGTTGACACG ACTGCTTGAG 660 AGTCAGCATA TCCAAGTACC TTCCGTTTCT CCGGCTACGG CCTCACAAAG CAATCAAGAT 720 GAATCACCTA CACCCGCGCA G ATG GTA AGC GCG TCT GGA ACA GCG ACG AAG 771 Met Val Ser Ala Ser Gly Thr Ala Thr Lys 1 5 10 AAG CGA CGA CTA GAC TCC GAT GGA GAA ACG CCG CAA TCG AGC GTA TCT 819 Lys Arg Arg Leu Asp Ser Asp Gly Glu Thr Pro Gin Ser Ser Val Ser 15 20 25 TCA CCA GGC ACC CAG AAT CCA GAC ATC TCT GAC ATC CAA CGA CTT GAT 867 Ser Pro Gly Thr Gin Asn Pro Asp He Ser Asp He Gin Arg Leu Asp 30 35 40 CGG GTA CTC TCC TAT GAG CTG CAA CAG CGA ACG CTG ACT CGC TAT GTC 915 Arg Val Leu Ser Tyr Glu Leu Gin Gin Arg Thr Leu Thr Arg Tyr Val 45 50 55 ACC GAG ATA GCA CCA CTC TTC CCA GCA GTG CCA GCG CCA GCG GAT TGC 963 Thr Glu He Ala Pro Leu Phe Pro Ala Val Pro Ala Pro Ala Asp Cys 60 65 70 TCG TTG CCC GAA ATG AGA GCG AAT CGA CCC ACG TTG CTT ATG GCT TTC 1011 Ser Leu Pro Glu Met Arg Ala Asn Arg Pro Thr Leu Leu Met Ala Phe 75 80 85 90 TTA TAT GCT GCC AGT TGC GGC TTT CTT TCG CTT GAT ACT CAA GAA GAT 1059 Leu Tyr Ala Ala Ser Cys Gly Phe Leu Ser Leu Asp Thr Gin Glu Asp 95 100 105 GTA GCT CAA ATT CTG CTC AAT ACC CTC TCT GCA AGA GCA ATC ACG CAC 1107 Val Ala Gin He Leu Leu Asn Thr Leu Ser Ala Arg Ala He Thr His 110 115 120 GGA GAG GAG ACG CTT GAA TTG ATA CAA GCT ATT CAG ATT GCC TGC TTG 1155 Gly Glu Glu Thr Leu Glu Leu He Gin Ala He Gin He Ala Cys Leu 125 130 135 TGG TAT CGC TCA CCG AAG CAC CAT CGA CGT GCG GCC GTC TAC CAG CTC 1203 Trp Tyr Arg Ser Pro Lys His His Arg Arg Ala Ala Val Tyr Gin Leu 140 145 150 ATT GAC ATC GCT TCT GCC ATG GCC AAT GGT CTC AGC GCA GGC GGT CCA 1251 He Asp He Ala Ser Ala Met Ala Asn Gly Leu Ser Ala Gly Gly Pro 155 160 165 170 CTC GCT CCT CCG ACC AAA GGA CTG ACT TTG GAC GAT TGC GCG GAT ACG 1299 Leu Ala Pro Pro Thr Lys Gly Leu Thr Leu Asp Asp Cys Ala Asp Thr 175 180 185 GGG TCG TAC GAG TCG GTA GAG GGC TGG CGC GCC TGG CTT GGC TGC CAT 1347 Gly Ser Tyr Glu Ser Val Glu Gly Trp Arg Ala Trp Leu Gly Cys His 190 195 200 GTA CTG TCT GTC TCT ATG GCC ATT TTC ATG AGG AAA TCG ATG ACT GCA 1395 Val Leu Ser Val Ser Met Ala He Phe Met Arg Lys Ser Met Thr Ala 205 210 215 AGT TGG ACC GAA CAG CAC GAG CAG GCA CGT CTG ATG CTG CAG TAC TCG 1443 Ser Trp Thr Glu Gin His Glu Gin Ala Arg Leu Met Leu Gin Tyr Ser 220 225 230 CCC TTG AAC GCA GAC TCT GAT AGG TGG CTT GCT CAG TAC ATC AGA GCC 1491 Pro Leu Asn Ala Asp Ser Asp Arg Trp Leu Ala Gin Tyr He Arg Ala 235 240 245 250 GAG CGA CTA TGC GAA GAG GTT TCT GAA CAG GTG GAT TTG ACT AAC ACA 1539 Glu Arg Leu Cys Glu Glu Val Ser Glu Gin Val Asp Leu Thr Asn Thr 255 260 265 TCT TTC TAT CGC GAC GTT GCT GAT CCT GCA ACA AGA AAT CCA GTG CAG 1587 Ser Phe Tyr Arg Asp Val Ala Asp Pro Ala Thr Arg Asn Pro Val Gin 270 275 280 ACA TGT CGA AAC AAG ATT CTG AAT TGG AAA ATG GGT GTT CCG CAA AGG 1635 Thr Cys Arg Asn Lys He Leu Asn Trp Lys Met Gly Val Pro Gin Arg 285 290 295 TTA CGC TCT CCG TTG ATC ATG TTC TGG GAA CAT GTA GCA ACA GCA TAC 1683 Leu Arg Ser Pro Leu He Met Phe Trp Glu His Val Ala Thr Ala Tyr 300 305 310 ATG CAT GAA CCA GTC CTG CAC ACA GCA ACG AAC AAG GAC AGC TTT ACG 1731 Met His Glu Pro Val Leu His Thr Ala Thr Asn Lys Asp Ser Phe Thr 315 320 325 330 GCA CCT TAT TTG GCA GAA AGG CTG TCA CTG ACA GAC TTT CCG ACT CCG 1779 Ala Pro Tyr Leu Ala Glu Arg Leu Ser Leu Thr Asp Phe Pro Thr Pro 335 340 345 CTC GTC ACT CAA GAT CAC ATC ACA GCT GTG TAC GAG CTG ACT GCG GCT 1827 Leu Val Thr Gin Asp His He Thr Ala Val Tyr Glu Leu Thr Ala Ala 350 355 360 GTA CAA GCC GTT CTG GAC ATC TTT ATC AAC TAC GAC ACT AAA TCT CTC 1875 Val Gin Ala Val Leu Asp He Phe He Asn Tyr Asp Thr Lys Ser Leu 365 370 375 GTT GCC TCT CCG AGC TTG GTG TAT GCT GCC AGA GCT GCG TAT GCG CTC 1923 Val Ala Ser Pro Ser Leu Val Tyr Ala Ala Arg Ala Ala Tyr Ala Leu 380 385 390 TAT GTT CTG GCG AAG CTA TAC ATC GCT GTC ACT GCA CCA GGA AAT ACA 1971 Tyr Val Leu Ala Lys Leu Tyr He Ala Val Thr Ala Pro Gly Asn Thr 395 400 405 410 CTT GGC ACA ATT CTG GAC GCC AGT ATT CTT GCC CTG CCG GAG TAC GCT 2019 Leu Gly Thr He Leu Asp Ala Ser He Leu Ala Leu Pro Glu Tyr Ala 415 420 425 GAC AGG CTG GCA ACA TGC GGC TCA CGA ATT AGA GCG CTC GAT GAG CGT 2067 Asp Arg Leu Ala Thr Cys Gly Ser Arg He Arg Ala Leu Asp Glu Arg 430 435 440 TGC GGT CCG GCT CGA ATC ATG CAT TGC GCA CCG GCG ATC AAG GAC TGG 2115 Cys Gly Pro Ala Arg He Met His Cys Ala Pro Ala He Lys Asp Trp 445 450 455 TAT CTG AAC TAT ACT CAA TTC CTC TCC TCG AAC GCT GCA CTC GCC CAG 2163 Tyr Leu Asn Tyr Thr Gin Phe Leu Ser Ser Asn Ala Ala Leu Ala Gin 460 465 470 TCG ATC CAG GTC TCC AAC GAC AAT GTG GCG GAG GCT CAG ATG ACT TTG 2211 Ser He Gin Val Ser Asn Asp Asn Val Ala Glu Ala Gin Met Thr Leu 475 480 485 490 CCG CCG CTC CAA GAC AAC ACG AAC GCA TTT AGC AAT ATT CCA CCG GAT 2259 Pro Pro Leu Gin Asp Asn Thr Asn Ala Phe Ser Asn He Pro Pro Asp 495 500 505 TGG GAG AAT CTG CTC ATG TTC GGT GAT AGT TCC ACG GAC TAT GGC TTC 2307 Trp Glu Asn Leu Leu Met Phe Gly Asp Ser Ser Thr Asp Tyr Gly Phe 510 515 520 GAT CAG CTG TTT GCT GAA CCT ATT CCT CTA CAG CTC GAG CAG CCC ATA 2355 Asp Gin Leu Phe Ala Glu Pro He Pro Leu Gin Leu Glu Gin Pro He 525 530 535 TTT GCC AAT ACG ATA CCT ACT GCG TTT GCG ACG AAG TGATCCAACA 2401 Phe Ala Asn Thr He Pro Thr Ala Phe Ala Thr Lys 540 545 550 CGCGGCAAGA CGGGATCTCT GCTGTCAACG AAGCAGCGCA TGAAGCTCCA GAATGGGGAT 2461 CACATACCGA CGTTACGTTC TTCTTGGGCG AAGAAGAAGA CTTGCATCAT CAGCGTACTG 2521 CATCGTCGAA GTCGGTGATC CACGAACAAA TCGATGGCTC GGCTCGCATG CCATCAATCC 2581 GAAAATTTGC GATGATTGGG CACACTCGTC TTTGCGGAGC TCTGCCATAA GTCGCGCTTG 2641 GAAGACTTCG TGGCAACGAT CGATGCGTCA GCTGCAGAAA GGCCGGTTCT TTGAATTGCC 2701 GTGTTAGCAG AGGCAGTACT GAACAAGTCC GCACCCTTAG ATGTCTGCAT CCTGCAAAAT 2761 GGCGAATGTC CGATCAGAGC TCGACAAAAA TTGTCAATGG GGTCTTGAGG TGTGCCCATA 2821 TTGAGGAGCG ATGGAAGACC GCACGTCTGC GAAGTCGTCT GTGGATGAAG AAGTCTGCAT 2881 TCTGCGCATG TAACCTCGTA CATGTGCACT GTCGGAAATA GCTGGAGCAA GTGGGCTAAG 2941 GTTACCCGAA GTGGAACATT AGCCAAGCTC CATCGGCGCG ATTGCTCGAT GTTATCGAGT 3001 CATGGAAACC AGGATGACAG TCCCGCGCCA GCGCCGCCCA CGTGCAACTA TCAGACTATC 3061 TATCTCAGTG CTATCTACTG ATAAGCACGA GGGATCACGA CGAACGGAAT CGACAGCGAT 3121 GACCATGAAA AGCTGCCGGA CACATGGGTT CACATCATTC ATCTGCAGTT GTGAAAACCT 3181 TTCGCCTGCA CATCAGTCCA TCGGTTGTGG GGTCTCGCGA CATGCAATTC TTTATAATAA 3241 GTACTGTTCG TCCACATGAG TGACGCGATA CAAGTGGCCA GCAGAGCCTG CTGTCAAATC 3301 CCTGTTTCGT CACCGGACGA TCACGGGCGC TGCTCAGAAT CAACACCTTT GCTTCAAGAC 3361 TCAATGTCCT CGGGTGGTCA TCGCAATATG TCGTCCAGCA TGGAGAAATT CAAGAATTC 3420 (2) INFORMATION FOR SEQ ID NO : 9 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 550 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 9 : Met Val Ser Ala Ser Gly Thr Ala Thr Lys Lys Arg Arg Leu Asp Ser 1 5 10 15 Asp Gly Glu Thr Pro Gin Ser Ser Val Ser Ser Pro Gly Thr Gin Asn 20 25 30 Pro Asp He Ser Asp He Gin Arg Leu Asp Arg Val Leu Ser Tyr Glu 35 40 45 Leu Gin Gin Arg Thr Leu Thr Arg Tyr Val Thr Glu He Ala Pro Leu 50 55 60 Phe Pro Ala Val Pro Ala Pro Ala Asp Cys Ser Leu Pro Glu Met Arg 65 70 75 80 Ala Asn Arg Pro Thr Leu Leu Met Ala Phe Leu Tyr Ala Ala Ser Cys 85 90 95 Gly Phe Leu Ser Leu Asp Thr Gin Glu Asp Val Ala Gin He Leu Leu 100 105 110 Asn Thr Leu Ser Ala Arg Ala He Thr His Gly Glu Glu Thr Leu Glu 115 120 125 Leu He Gin Ala He Gin He Ala Cys Leu Trp Tyr Arg Ser Pro Lys 130 135 140 His His Arg Arg Ala Ala Val Tyr Gin Leu He Asp He Ala Ser Ala 145 150 155 160 Met Ala Asn Gly Leu Ser Ala Gly Gly Pro Leu Ala Pro Pro Thr Lys 165 170 175 Gly Leu Thr Leu Asp Asp Cys Ala Asp Thr Gly Ser Tyr Glu Ser Val 180 185 190 Glu Gly Trp Arg Ala Trp Leu Gly Cys His Val Leu Ser Val Ser Met 195 200 205 Ala He Phe Met Arg Lys Ser Met Thr Ala Ser Trp Thr Glu Gin His 210 215 220 Glu Gin Ala Arg Leu Met Leu Gin Tyr Ser Pro Leu Asn Ala Asp Ser 225 230 235 240 Asp Arg Trp Leu Ala Gin Tyr He Arg Ala Glu Arg Leu Cys Glu Glu 245 250 255 Val Ser Glu Gin Val Asp Leu Thr Asn Thr Ser Phe Tyr Arg Asp Val 260 265 270 Ala Asp Pro Ala Thr Arg Asn Pro Val Gin Thr Cys Arg Asn Lys He 275 280 285 Leu Asn Trp Lys Met Gly Val Pro Gin Arg Leu Arg Ser Pro Leu He 290 295 300 Met Phe Trp Glu His Val Ala Thr Ala Tyr Met His Glu Pro Val Leu 305 310 315 320 His Thr Ala Thr Asn Lys Asp Ser Phe Thr Ala Pro Tyr Leu Ala Glu 325 330 335 Arg Leu Ser Leu Thr Asp Phe Pro Thr Pro Leu Val Thr Gin Asp His 340 345 350 He Thr Ala Val Tyr Glu Leu Thr Ala Ala Val Gin Ala Val Leu Asp 355 360 365 He Phe He Asn Tyr Asp Thr Lys Ser Leu Val Ala Ser Pro Ser Leu 370 375 380 Val Tyr Ala Ala Arg Ala Ala Tyr Ala Leu Tyr Val Leu Ala Lys Leu 385 390 395 400 Tyr He Ala Val Thr Ala Pro Gly Asn Thr Leu Gly Thr He Leu Asp 405 410 415 Ala Ser He Leu Ala Leu Pro Glu Tyr Ala Asp Arg Leu Ala Thr Cys 420 425 430 Gly Ser Arg He Arg Ala Leu Asp Glu Arg Cys Gly Pro Ala Arg He 435 440 445 Met His Cys Ala Pro Ala He Lys Asp Trp Tyr Leu Asn Tyr Thr Gin 450 455 460 Phe Leu Ser Ser Asn Ala Ala Leu Ala Gin Ser He Gin Val Ser Asn 465 470 475 480 Asp Asn Val Ala Glu Ala Gin Met Thr Leu Pro Pro Leu Gin Asp Asn 485 490 495 Thr Asn Ala Phe Ser Asn He Pro Pro Asp Trp Glu Asn Leu Leu Met 500 505 510 Phe Gly Asp Ser Ser Thr Asp Tyr Gly Phe Asp Gin Leu Phe Ala Glu 515 520 525 Pro He Pro Leu Gin Leu Glu Gin Pro He Phe Ala Asn Thr He Pro 530 535 540 Thr Ala Phe Ala Thr Lys 545 550 (2) INFORMATION FOR SEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 924 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..921 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: ATG GCA ACT GAA CTC CCC ACC ACA AAC GGC CAC AGC GCA CAG GAT GGC 48 Met Ala Thr Glu Leu Pro Thr Thr Asn Gly His Ser Ala Gin Asp Gly 1 5 10 15 GAG AAC AAC TTT GCC GTC AAG GCC GGT CTG GCA CGC ATG TTG AAG GGT 96 Glu Asn Asn Phe Ala Val Lys Ala Gly Leu Ala Arg Met Leu Lys Gly 20 25 30 GGA GTC ATC ATG GAC GTT GTC AAC GCT GAG CAA GCG CGG ATA GCA GAA 144 Gly Val He Met Asp Val Val Asn Ala Glu Gin Ala Arg He Ala Glu 35 40 45 GAA GCC GGT GCT TCA GCC GTC ATG GCC CTC GAG CGC GTG CCC GCA GAC 192 Glu Ala Gly Ala Ser Ala Val Met Ala Leu Glu Arg Val Pro Ala Asp 50 55 60 ATT CGA TCC CAA GGT GGT GTC GCA CGT ATG AGC GAC CCC AAG ATG ATC 240 He Arg Ser Gin Gly Gly Val Ala Arg Met Ser Asp Pro Lys Met He 65 70 75 80 AAG GAG ATC ATG GAC ACA GTC ACA ATC CCC GTC ATG GCC AAG GCG CGA 288 Lys Glu He Met Asp Thr Val Thr He Pro Val Met Ala Lys Ala Arg 85 90 95 ATT GGA CAC TTT GTC GAA TGC CAG ATC CTC GAA GCC CTA GGC GTA GAC 336 He Gly His Phe Val Glu Cys Gin He Leu Glu Ala Leu Gly Val Asp 100 105 110 TAC ATT GAC GAA TCC GAA GTC CTC ACC CCC GCC GAC GCT ATT CAC CAC 384 Tyr He Asp Glu Ser Glu Val Leu Thr Pro Ala Asp Ala He His His 115 120 125 GTC TCC AAG CAC CCC TTC CGC ATT CCC TTC GTC TGC GGC TGC CGG GGC 432 Val Ser Lys His Pro Phe Arg He Pro Phe Val Cys Gly Cys Arg Gly 130 135 140 CTC GGC GAA GCC CTT CGC CGC ATC TCG GAA GGT GCA GCC ATC ATC CGC 480 Leu Gly Glu Ala Leu Arg Arg He Ser Glu Gly Ala Ala He He Arg 145 150 155 160 ACA AAG GGC GAA GCC GGA ACC GGC GAC GTC ATT GAG GCT GTC CGC CAC 528 Thr Lys Gly Glu Ala Gly Thr Gly Asp Val He Glu Ala Val Arg His 165 170 175 ATG CGT ACC GTA AAC AGC GAG ATT GCC CGC GCA AAG AGC ATG TCA GAG 576 Met Arg Thr Val Asn Ser Glu He Ala Arg Ala Lys Ser Met Ser Glu 180 185 190 GAG GAG CTC CGT GTC TAC GCA AAG GAG CTT CAG GTC GAC TAT GCG CTG 624 Glu Glu Leu Arg Val Tyr Ala Lys Glu Leu Gin Val Asp Tyr Ala Leu 195 200 205 CTC AAG GAG ACG GCT AAG CTT GGT CGT CTG CCT GTT GTC AAC TTT GCG 672 Leu Lys Glu Thr Ala Lys Leu Gly Arg Leu Pro Val Val Asn Phe Ala 210 215 220 GCG GGT GGT GTC GCA ACA CCC GCT GAT GCT GCG TTG ATG ATG CAG TTG 720 Ala Gly Gly Val Ala Thr Pro Ala Asp Ala Ala Leu Met Met Gin Leu 225 230 235 240 GGT TGC GAT GGT GTC TTT GTT GGT AGC GGT ATC TTC AAG TCT GGA GAC 768 Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe Lys Ser Gly Asp 245 250 255 GCA GCC AAG AGG GCC AAG GCC ATC GTA CAG GCT GTT ACT CAC TAC AAA 816 Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Val Thr His Tyr Lys 260 265 270 GAC CCC AAG GTG CTC ATG GAA GTC AGC ATG GAT TTG GGT GAG GCC ATG 864 Asp Pro Lys Val Leu Met Glu Val Ser Met Asp Leu Gly Glu Ala Met 275 280 285 GTT GGT ATC AAC TGC GGT ACA ATG GGC GAG GAG GAG AAG CTT GCT AAG 912 Val Gly He Asn Cys Gly Thr Met Gly Glu Glu Glu Lys Leu Ala Lys 290 295 300 AGG GGA TGG TAG 924 Arg Gly Trp 305 (2) INFORMATION FOR SEQ ID NO: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 307 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: Met Ala Thr Glu Leu Pro Thr Thr Asn Gly His Ser Ala Gin Asp Gly 1 5 10 15 Glu Asn Asn Phe Ala Val Lys Ala Gly Leu Ala Arg Met Leu Lys Gly 20 25 30 Gly Val He Met Asp Val Val Asn Ala Glu Gin Ala Arg He Ala Glu 35 40 45 Glu Ala Gly Ala Ser Ala Val Met Ala Leu Glu Arg Val Pro Ala Asp 50 55 60 He Arg Ser Gin Gly Gly Val Ala Arg Met Ser Asp Pro Lys Met He 65 70 75 80 Lys Glu He Met Asp Thr Val Thr He Pro Val Met Ala Lys Ala Arg 85 90 95 He Gly His Phe Val Glu Cys Gin He Leu Glu Ala Leu Gly Val Asp 100 105 110 Tyr He Asp Glu Ser Glu Val Leu Thr Pro Ala Asp Ala He His His 115 120 125 Val Ser Lys His Pro Phe Arg He Pro Phe Val Cys Gly Cys Arg Gly 130 135 140 Leu Gly Glu Ala Leu Arg Arg He Ser Glu Gly Ala Ala He He Arg 145 150 155 160 Thr Lys Gly Glu Ala Gly Thr Gly Asp Val He Glu Ala Val Arg His 165 170 175 Met Arg Thr Val Asn Ser Glu He Ala Arg Ala Lys Ser Met Ser Glu 180 185 190 Glu Glu Leu Arg Val Tyr Ala Lys Glu Leu Gin Val Asp Tyr Ala Leu 195 200 205 Leu Lys Glu Thr Ala Lys Leu Gly Arg Leu Pro Val Val Asn Phe Ala 210 215 220 Ala Gly Gly Val Ala Thr Pro Ala Asp Ala Ala Leu Met Met Gin Leu 225 230 235 240 Gly Cys Asp Gly Val Phe Val Gly Ser Gly He Phe Lys Ser Gly Asp 245 250 255 Ala Ala Lys Arg Ala Lys Ala He Val Gin Ala Val Thr His Tyr Lys 260 265 270 Asp Pro Lys Val Leu Met Glu Val Ser Met Asp Leu Gly Glu Ala Met 275 280 285 Val Gly He Asn Cys Gly Thr Met Gly Glu Glu Glu Lys Leu Ala Lys 290 295 300 Arg Gly Trp 305

Claims: TH AT WHICH IS CLAIMED: 1. An isolated nucleic acid molecule which, upon expression, increases resistance in a cell to a photosensitizer. 2. An isolated nucleic acid molecule according to Claim 1, said molecule comprising a sequence selected from the group consisting of: (a) SEQ ID NO: 1; (b) nucleotides 825-1853 of SEQ ID NO:l; (c) sequences that encode a polypeptide comprising the amino acid sequence of SEQ ID NO:2; and (d) sequences that hybridize to a sequence of (a), (b) or (c), above, under stringent conditions. 3. An isolated nucleic acid molecule according to Claim 1 , wherein said photosensitizer produces singlet oxygen upon the reaction of said photosensitizer with light and oxygen. 4. An isolated nucleic acid molecule according to Claim 1, wherein said photosensitizer is cercosporin. 5. An isolated nucleic acid according to Claim 1, wherein said cell is a fungal cell. 6. An isolated nucleic acid molecule according to Claim 1, wherein said cell is a plant cell. 7. A transformed cell comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 1 operably linked with a promoter. 8. A transformed cell according to Claim 7, wherein said cell is a plant cell. 9. A method for increasing resistance to a photosensitizer in a cell, comprising transforming said cell with an nucleic acid molecule of Claim 1. 10. A method for increasing resistance to a photosensitizer in a cell according to Claim 9, wherein said photosensitizer produces singlet oxygen upon the reaction of said photosensitizer with light and oxygen. 11. A method for increasing resistance to a photosensitizer in a cell according to Claim 9, wherein said photosensitizer is cercosporin. 12. A method according to Claim 11, wherein said cell is a plant cell. 13. A method of increasing resistance in a cell to a pathogen, wherein the pathogen produces a photosensitizer, the method comprising transforming said cell with an isolated nucleic acid molecule of Claim 1. 14. A method according to Claim 13, wherein said photosensitizer is cercosporin. 15. A method according to Claim 13, wherein said pathogen is a fungus. 16. A method according to Claim 15, wherein said pathogen is selected from the group consisting of the Cercospora species. 17. A method of increasing resistance in an cell to singlet oxygen, comprising transforming said cell with an isolated nucleic acid molecule of Claim 1. 18. An expression cassette comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 1 operably linked with a promoter. 19. A transformed plant comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 1 operably linked with a promoter. 20. A transformed plant comprising an expression cassette according to Claim 18. 21. A method for increasing resistance to a photosensitizer in a plant, comprising transforming said plant with an expression cassette according to Claim 18. 22. A method according to Claim 21, wherein said photosensitizer is cercosporin. 23. A method according to Claim 21, wherein said plant is selected from the group consisting of rape, canola, sorghum, soybean, sugar beet, corn and tobacco. 24. A method for increasing resistance to infection by a fungal pathogen in a plant, wherein said fungal pathogen produces a photosensitizer, the method comprising transforming said plant with an expression cassette according to Claim 21. 25. A method according to Claim 24, wherein said fungal pathogen is selected from the group consisting of the Cercospora species. 26. A method according to claim 24, wherein said plant is selected from the group consisting of rape, canola, sorghum, soybean, sugar beet, corn and tobacco. 27. An isolated nucleic acid molecule which, upon expression, increases resistance in a cell to a photosensitizer. 28. An isolated nucleic acid molecule according to Claim 27, said molecule comprising a sequence selected from the group consisting of: (a) SEQ ID NO:8; (b) nucleotides 742-2391 of SEQ ID NO:8; (c) sequences that encode a polypeptide comprising the amino acid sequence of SEQ ID NO:9; and (d) sequences that hybridize to a sequence of (a), (b) or (c), above, under stringent conditions. 29. An isolated nucleic acid according to Claim 27, wherein said cell is a fungal cell or a plant cell. 30. A transformed cell comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 27 operably linked with a promoter. 31. A transformed cell according to Claim 30, wherein said cell is a plant cell. 32. A method for increasing resistance to cercosporin in a cell, comprising transforming said cell with an nucleic acid molecule of Claim 27. 33. A method according to Claim 32, wherein said cell is a plant cell. 34. A method of increasing resistance in a cell to a pathogen, wherein the pathogen produces cercosporin, the method comprising transforming said cell with an isolated nucleic acid molecule of Claim 27. 35. A method according to Claim 34, wherein said pathogen is a fungus. 36. A method according to Claim 35, wherein said pathogen is selected from the group consisting of the Cercospora species. 37. An expression cassette comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 27 operably linked with a promoter. 38. A transformed plant comprising a chimeric gene, said gene comprising a nucleotide sequence according to Claim 27 operably linked with a promoter. 39. A transformed plant comprising an expression cassette according to Claim 37. 40. A method for increasing resistance to cercosporin in a plant, comprising transforming said plant with an expression cassette according to Claim 37. 41. A method according to Claim 40, wherein said plant is selected from the group consisting of rape, canola, sorghum, soybean, sugar beet, corn and tobacco. 42. A method for increasing resistance to infection by a fungal pathogen in a plant, wherein said fungal pathogen produces cercosporin, the method comprising transforming said plant with an expression cassette according to Claim 37. 43. A method according to Claim 42, wherein said fungal pathogen is selected from the group consisting of the Cercospora species. 44. A method according to claim 42, wherein said plant is selected from the group consisting of rape, canola, sorghum, soybean, sugar beet, corn and tobacco. 45. A method of selecting, from a plurality of cells, those cells expressing a heterologous DNA sequence, comprising: (a) subjecting a cells to a transformation procedure using a DNA construct comprising a heterologous DNA sequence and a DNA sequence according to claim 2, said cells from an organism unable to grow in the absence of exogenous pyridoxine; and then (b) growing said cells on medium lacking pyridoxine; wherein cells able to grow on said medium have been successfully transformed by said DNA construct and express said heterologous DNA sequence. 46. A method according to claim 45 wherein said cells are selected from fungal cells and plant cells.

Inventors: DAUB MARGARET E, EHRENSHAFT MARILYN, JENNS ANNE E, DAUB, MARGARET, E., EHRENSHAFT, MARILYN, JENNS, ANNE, E.
Applicants: DAUB MARGARET E, EHRENSHAFT MARILYN, JENNS ANNE E, UNIV NORTH CAROLINA, DAUB, MARGARET, E., EHRENSHAFT, MARILYN, JENNS, ANNE, E., NORTH CAROLINA STATE UNIVERSITY
Application year: 1998
Main classification: A01H1
IPC codes: C07K14, C12N15