GENETICALLY ENGINEERED MODIFICATION OF POTATO TO FORM AMYLOPECTIN-TYPE STARCH

Abstract: Genetically engineered modification of potato for suppressing the formation of amylose-type starch is described. Three fragments for insertion in the antisense direction into the potato genome are also described. Moreover, antisense constructs, genes and vectors comprising said antisense fragments are described. Further a promoter for the gene coding for formation of granule-bound starch synthase and also the gene itself are described. Also cells, plants, tubers, microtubers and seeds of potato comprising said antisense fragments are described. Finally, amylopectin-type starch, both native and derivatised, derived from the potato that is modified in a genetically engineered manner, as well as a method of suppressing amylose formation in potato are described.

Description: GENETICALLY ENGINEERED MODIFICATION OF POTATO TO FORM AMYLOPECTIN-TYPE STARCH The present invention relates to genetically engi- neered modification of potato, resulting in the formation of practically solely amylopectin-type starch in the pota¬ to. The genetically engineered modification implies the insertion of gene fragments into potato, said gene frag¬ ments comprising parts of leader sequence, translation start, translation end and trailer sequence as well as coding and noncoding (i.e. exons and introns) parts of the gene for granule-bound starch synthase, inserted in the antisense direction. Background of the Invention Starch in various forms is of great import in the food and paper industry. In future, starch will also be a great potential for producing polymers which are degrad- able in nature, e.g. for use as packing material. Many different starch products are known which are produced by derivatisation of native starch originating from, inter alia, maize and potato. Starch from potato and maize, respectively, is competing in most market areas. In the potato tuber, starch is the greatest part of the solid matter. About 1/4 to 1/5 of the starch in potato is amylose, while the remainder of the starch is a ylo- pectin. These two components of the starch have different fields of application, and therefore the possibility of producing either pure amylose or pure amylopectin is most interesting. The two starch components can be produced from common starch, which requires a number of process steps and, consequently, is expensive and complicated. It has now proved that by genetic engineering it is possible to modify potato so that the tubers merely pro¬ duce mainly starch of one or the other type. As a result, a starch quality is obtained which can compete in the areas where potato starch is normally not used today. Starch from such potato which is modified in a genetically engineered manner has great potential as a food additive, since it has not been subjected to any chemical modifica¬ tion process. Starch Synthesis The synthesis of starch and the regulation thereof are presently being studied with great interest, both on the level of basic research and for industrial application. Although much is known about the assistance of certain enzymes in the transformation of saccharose into starch, the biosynthesis of starch has not yet been elucidated. By making researches above all into maize, it has, however, been possible to elucidate part of the ways of synthesis and the enzymes participating in these reac¬ tions. The most important starch-synthesising enzymes for producing the starch granules are the starch synthase and the branching enzyme. In maize, three forms of starch syn¬ thase have so far been demonstrated and studied, two of which are soluble and one is insolubly associated with the starch granules. Also the branching enzyme consists of three forms which are probably coded by three different genes (Mac Donald & Preiss, 1985; Preiss, 1988). The Waxy Gene in Maize The synthesis of the starch component amylose essen¬ tially occurs by the action of the starch synthase alpha- -l,4-D-glucane-4-alpha-glucosyl transferase (EC 2.4.1.21) which is associated with the starch granules in the growth cell. The gene coding for this granule-bound enzyme is called "waxy" (= wx ), while the enzyme is called "GBSS" (granule-bound starch synthase). waxy locus in maize has been thoroughly characterised both genetically and biochemically. The waxy gene on chro¬ mosome 9 controls the production of amylose in endosperm, pollen and the embryo sac. The starch formed in endosperm in normal maize with the wx allele consists to 25% of amylose and to 75% of amylopectin. A mutant form of maize has been found in which the endosperm contains a mutation located to the wx gene, and therefore no functioning GBSS is synthesised. Endosperm from this mutant maize therefore contains merely amylopectin as the starch component. This so-called waxy mutant thus contains neither GBSS nor amy¬ lose (Echt & Schwartz, 1981). The GBSS protein is coded by the wx gene in the cell nucleus but is transported to and active in the amylo- plast. The preprotein therefore consists of two compo¬ nents, viz. a 7 kD transit peptide which transfers the protein across the amyloplast membrane, and the actual protein which is 58 kD. The coding region of the wx gene in maize is 3.7 kb long and comprises 14 exons and 13 introns. A number of the regulation signals in the pro¬ moter region are known, and two different polyadenylating sequences have been described (Klδsgen et al, 1986; Schwartz-Sommer et al, 1984; Shure et al, 1983). Amylose Enzyme in Potato In potato, a 60 kD protein has been identified, which constitutes the main granule-bound protein. Since antibo¬ dies against this potato enzyme cross-react with GBSS from maize, it is assumed that it is the granule-bound synthase (Vos-Scheperkeuter et al, 1986). The gene for potato GBSS has, however, so far not been characterised to the same extent as the waxy gene in maize, either in respect of locating or structure. Naturally occurring waxy mutants have been described for barley, rice and sorghum besides maize. In potato no natural mutant has been found, but a mutant has been pro¬ duced by X-radiation of leaves from a monohaploid (n=12) plant (Visser et al, 1987). Starch isolated from tubers of this mutant contains neither the GBSS protein nor amylose. The mutant is conditioned by a simple recessive gene and is called amf. It may be compared to waxy mutants of other plant species since both the GBSS protein and amylose are lacking. The stability of the chromosome number, however, is weakened since this is quadrupled to the natural number (n=48), which can give negative effects on the potato plants (Jacobsen et al, 1990). Inhibition of Amylose Production The synthesis of amylose can be drastically reduced by inhibition of the granule-bound starch synthase, GBSS, which catalyses the formation of amylose. This inhibition results in the starch mainly being amylopectin. Inhibition of the formation of enzyme can be accom¬ plished in several ways, e.g. by: - mutagen treatment which results in a modification of the gene sequence coding for the formation of the enzyme - incorporation of a transposon in the gene sequence cod¬ ing for the enzyme - genetically engineered modification so that the gene coding for the enzyme is not expressed, e.g. antisense gene inhibition. Fig. 1 illustrates a specific suppression of normal gene expression in that a complementary antisense nucleo- tide is allowed to hybridise with mRNA for a target gene. The antisense nucleotide thus is antisense RNA which is transcribed in vivo from a "reversed" gene sequence (Izant, 1989). By using the antisense technique, various gene func¬ tions in plants have been inhibited. The antisense con¬ struct for chalcone synthase, polygalacturonase and phos- phinotricin acetyltransferase has been used to inhibit the corresponding enzyme in the plant species petunia, tomato and tobacco. Inhibition of Amylose in Potato In potato, experiments have previously been made to inhibit the synthesis of the granule-bound starch synthase (GBSS protein) with an antisense construct corresponding to the gene coding for GBSS (this gene is hereinafter called the "GBSS gene"). Hergersberger (1988) describes a method by which a cDNA clone for the GBSS gene in potato has been isolated by means of a cDNA clone for the wx + gene in maize. An antisense construct based on the entire cDNA clone was transferred to leaf discs of potato by means of Agrobacterium tumefaciens. In microtubers induced in vitro from regenerated potato sprouts, a varying and very weak reduction of the amylose content was observed and shown in a diagram. A complete characterisation of the GBSS gene is not provided. The gene for the GBSS protein in potato has been fur¬ ther characterised in that a genomic wx clone was examin¬ ed by restriction analysis. However, the DNA sequence of the clone has not been determined (Visser et al, 1989). Further experiments with an antisense construct cor- responding to the GBSS gene in potato have been reported. The antisense construct which is based on a cDNA clone together with the CaMV 35S promoter has been transformed by means of Agrobacterium rhizogenes. According to infor¬ mation, the transformation resulted in a lower amylose content in the potato, but no values have been accounted for (Flavell, 1990). None of the methods used so far for genetically engi¬ neered modification of potato has resulted in potato with practically no amylose-type starch. The object of the invention therefore is to provide a practically complete suppression of the formation of amy¬ lose in potato tubers. Summary of the Invention According to the invention, the function of the GBSS gene and, thus, the amylose production in potato are inhi¬ bited by using completely new antisense constructs. For forming the antisense fragments according to the inven¬ tion, the genomic GBSS gene is used as a basis in order to achieve an inhibition of GBSS and, consequently, of the amylose production, which is as effective as possible. The antisense constructs according to the invention comprise both coding and noncoding parts of the GBSS gene which correspond to sequences in the region comprising promoter as well as leader sequence, translation start, translation end and trailer sequence in the antisense direction. For a tissue-specific expression, i.e. the amylose production should be inhibited in the potato tubers only, use is made of promoters which are specifically active in the potato tuber. As a result, the starch composition in other parts of the plant is not affected, which otherwise would give negative side-effects. The invention thus comprises a fragment which essen¬ tially has one of the nucleotide sequences stated in SEQ ID No. 1, SEQ ID No. 2 or SEQ ID No. 3. However, the sequences may deviate from those stated by one or more non-adjacent base pairs, without affecting the function of the fragments. The invention also comprises a potato-tuber-specific promoter comprising 987 bp which belongs to the gene according to the invention, which codes for granule-bound starch synthase. Neither the promoter nor the correspond- ing gene has previously been characterised. The promoter sequence of 987 bp is stated in SEQ ID No. 4, while the gene sequence is stated in SEQ ID No. 5. Also the promoter and gene sequences may deviate from those stated by one or more non-adjacent base pairs, without affecting their function. The invention also comprises vectors including the antisense fragments and the antisense constructs according to the invention. In other aspects the invention comprises cells, plants, tubers, microtubers and seeds whose genome con¬ tains the fragments according to the invention inserted in the antisense direction. In still further aspects, the invention comprises amylopectin-type starch, both native and derivatised. Finally, the invention comprises a method of sup¬ pressing amylose formation in potato, whereby mainly amylopectin-type starch is formed in the potato. The invention will now be described in more detail with reference to the accompanying Figures in which Fig. 1 illustrates the principle of the antisense gene inhibition, Fig. 2 shows the result of restriction analysis of the potato GBSS gene, Fig. 3 shows two new binary vectors pHo3 and pHo4, Fig. 4 shows the antisense constructs pHoxwA, pHoxwB and pHoxwD, Fig. 5 shows the antisense constructs pHoxwF and pHoxwG, and Fig. 6 shows the antisense constructs pHoxwK and pHoxwL. Moreover, the sequences of the different DNA frag¬ ments according to the invention are shown in SEQ ID Nos 1, 2, 3, 4 and 5. There may be deviations from these sequences in one or more non-ad acent base pairs. MATERIALS In the practical carrying out of the invention the following materials were used: Bacterial strains: E. coli DH5alfa and DHδalfaF'IQ(BRL). E. coli JM105 (Pharmacia). A. tumefaciens LBA4404 (Clon- tech). Vectors: M13mpl8 and mpl9 (Pharmacia). pBIlOl and pBI121 (Clontech). pBl240.7 (M. W. Bevan). pUC plasmids (Pharma¬ cia). Enzymes: Restriction enzymes and EcoRI linker (BRL). TM TM UNION DNA Ligation Kit (Clontech). Sequenase DNA Sequencing Kit (USB). T.-DNA ligase (Pharmacia). The above-mentioned materials are used according to specifications stated by the manufacturers. Genomic Library A genomic library in EMBL3 has been produced by Clon- tech on the applicant's account, while using leaves of the potato Bint e as starting material. Identification and Isolation of the GBSS Gene The genomic library has been screened for the potato GBSS gene by means of cDNA clones for both the 5' and 3' end of the gene (said cDNA clones being obtained from M Hergersberger, Max Plank Institute in Cologne) according to a protocol from Clontech. A full-length clone of the potato GBSS gene, wx311, has been identified and isolated from the genomic library. The start of the GBSS gene has been determined at an EcoRI fragment which is called fragment w (3.95 kb). The end of the GBSS gene has also been determined at an EcoRI frag¬ ment which is called fragment x (5.0 kb). A Bglll-Spel fragment which is called fragment m (3.9 kb) has also been isolated and shares sequences both from fragment w and from fragment x. The fragments w, m and x have been sub- cloned in pUC13 (Viera, 1982; Yanisch-Peron et al, 1985) and are called pSw, pSm and pSx, respectively (Fig. 2). Characterisation of the GBSS Gene in Potato The GBSS gene in potato has been characterised by restriction analysis and cDNA probes, where the 5' and 3' end of the GBSS gene has been determined more accurately (Fig. 2). Sequence determination according to Sanger et al, 1977 of the GBSS gene has been made on subclones from pSw and pSx in M13mpl8 and mpl9 as well as pUC19 starting around the 5' end (see SEQ ID No. 5). The promoter region has been determined at a Bglll-Nsil fragment (see SEQ ID No. 4). Transcription and translation start has been determined at an overlapping Bglll-Hindlll fragment. The terminator region has in turn been determined at a Spel-Hindlll fragment. Antisense Constructs for the GBSS Gene in Potato The GBSS gene fragments according to the invention (see SEQ ID Nos 1, 2 and 3, and Fig. 2) have been deter¬ mined in the following manner. The restriction of pSw with Nsil and Hindlll gives fragment I (SEQ ID No. 1) which subcloned in pUC19 is called 19NH35. Further restriction of 19 NH35 with Hpal- Sstl gives a fragment containing 342 bp of the GBSS gene according to the invention. This fragment comprises leader sequence, translation start and the first 125 bp of the coding region. The restriction of pSm with Hpal and Nsil gives frag¬ ment II (SEQ ID No. 2) which subcloned in pJRD184 (Heus- terspreute et al, 1987) is called pJRDmitt. Further restriction of pJRDmitt with Hpal-SstI gives a fragment containing 2549 bp of the GBSS gene according to the invention. This fragment comprises exons and introns from the middle of the gene. The restriction of pSx with SstI and Spel gives frag¬ ment III (SEQ ID No. 3) which subcloned in pBluescript (Melton et al, 1984) is called pBlue3'. Further restric¬ tion of pBlue3' with BamHI-SstI gives a fragment contain¬ ing 492 bp of the GBSS gene according to the invention. This fragment comprises the last intron and exon, transla¬ tion end and 278 bp of trailer sequence. Antisense Constructs with Fragment I (Fig. 4): For the antisense construct pHoxwA, the Hpal-SstI fragment from 19NH35 has been inserted in the antisense direction into the binary vector pBI121 (Jefferson et al, 1987) cleaved with Smal-Sstl. The transcription of the antisense frag- ment is then initiated by the CaMV 35S promoter and is terminated by the NOS terminator (NOS = nopaline syn¬ thase). For the antisense construct pHoxwB, the Hpal-SstI fragment from 19NH35 has been inserted in the antisense direction into the binary vector pHo4 (Fig. 3) cleaved with Smal-Sstl. The patatin I promoter which is tuber specific in potato comes from the vector pBl240.7 obtain¬ ed from M. Bevan, Institute of Plant Science Research, Norwich. The transcription of the antisense fragment is then initiated by the patatin I promoter and is terminated by the NOS terminator. For the antisense construct pHoxwD, the Hpal-SstI fragment from 19NH35 has been inserted in the antisense direction into the binary vector pHo3 (Fig. 3) cleaved with Smal-Sstl. pHo3 is a new binary vector which is con¬ structed on the basis of pBIlOl. This vector which con¬ tains the promoter according to the invention (see SEQ ID No. 4) (GBSS promoter) of the now characterised potato GBSS gene according to the invention has been restriction- cleaved with Smal and Sstl, the Hpal-SstI fragment from 19NH35 being inserted in the antisense direction. The transcription of the antisense fragment is then initiated by its own GBSS promoter and is terminated by the NOS ter¬ minator. This means that the antisense fragment is tran¬ scribed only in the potato tuber, since the GBSS promoter like the patatin I promoter is tuber-specific. Antisense Constructs with Fragment II (Fig. 5): For the antisense construct pHoxwF, the Hpal-SstI fragment from pJRDmitt has been inserted in the antisense direction into the binary vector pHo4 cleaved with Smal-Sstl. The tran¬ scription of the antisense fragment is then initiated by the patatin I promoter and terminated by the NOS termi¬ nator. For the antisense construct pHoxwG, the Hpal-SstI fragment from pJRDmitt has been inserted in the antisense direction into the binary vector pHo3 cleaved with Smal- Sstl. The transcription of the antisense fragment is then initiated by its own GBSS promoter and is terminated by the NOS terminator. Antisense Constructs with Fragment III (Fig. 6): For the antisense construct pHoxwK, the BamHI-SstI fragment from pBlue3' has been inserted in the antisense direction into the binary vector pHo4 cleaved with BamHI-SstI. The tran¬ scription of the antisense fragment is then initiated by the patatin I promoter and is terminated by the NOS termi¬ nator. For the antisense construct pHoxwL, the BamHI-SstI fragment from pBlue3' has been inserted in the antisense direction into the binary vector pHo3 cleaved with BamHI- SstI. The transcription of the antisense fragment is then initiated by its own GBSS promoter and is terminated by the NOS terminator. The formed antisense constructs (Figs 4, 5, 6) have been transformed to Agrobacterium tumefaciens strain LBA4404 by direct transformation with the "freeze-thawing" method (Hoekema et al, 1983; An et al, 1988). Transformation The antisense constructs are transferred to bacteria, suitably by the "freeze-thawing" method (An et al, 1988). The transfer of the recombinant bacterium to potato tissue occurs by incubation of the potato tissue with the recom- binant bacterium in a suitable medium after some sort of damage has been inflicted upon the potato tissue. During the incubation, T-DNA from the bacterium enters the DNA of the host plant. After the incubation, the bacteria are killed and the potato tissue is transferred to a solid medium for callus induction and is incubated for growth of callus. After passing through further suitable media, sprouts are formed which are cut away from the potato tissue. Checks for testing the expression of the antisense constructs and the transfer thereof to the potato genome are carried out by e.g. southern and northern hybridisa¬ tion (Maniatis et al (1982)). The number of copies of the antisense construct which has been transferred is deter¬ mined by southern hybridisation. The testing of the expression on protein level is suitably carried out on microtubers induced in vitro on the transformed sprouts, thus permitting the testing to be performed as quickly as possible. Characterisation of the GBSS Protein The effect of the antisense constructs on the func¬ tion of the GBSS gene with respect to the activity of the GBSS protein is examined by extracting starch from the microtubers and analysing it regarding the presence of the GBSS protein. In electrophoresis on polyacrylamide gel (Hovenkamp-Hermelink et al, 1987), the GBSS protein forms a distinct band at 60 kD, when the GBSS gene functions. When the GBSS gene is not expressed, i.e. when the anti- sense GBSS gene is fully expressed, thereby inhibiting the formation of GBSS protein, no 60 kD band is demonstrated on the gel. Characterisation of the Starch The composition of the starch in microtubers is iden¬ tical with that of ordinary potato tubers, and therefore the effect of the antisense constructs on the amylose pro¬ duction is examined in microtubers. The proportion of amy¬ lose to amylopectin can be determined by a spectrophoto- metric method (e.g. according to Hovenkamp-Hermelink et al, 1988). Extraction of Amylopectin from Amylopectin Potato Amylopectin is extracted from the so-called amylo¬ pectin potato (potato in which the formation of amylose has been suppressed by inserting the antisense constructs according to the invention) in a known manner. Derivatisation of Amylopectin Depending on the final use of the amylopectin, its physical and chemical qualities can be modified by deri- vatisation. By derivatisation is here meant chemical, phy¬ sical and enzymatic treatment and combinations thereof (modified starches). The chemical derivatisation, i.e. chemical modifica¬ tion of the amylopectin, can be carried out in different ways, for example by oxidation, acid hydrolysis, dextri- nisation, different forms of etherification, such as cationisation, hydroxy propylation and hydroxy ethylation, different forms of esterification, for example by vinyl acetate, acetic anhydride, or by monophosphatising, diphosphatising and octenyl succination, and combina¬ tions thereof. Physical modification of the amylopectin can be effected by e.g. cylinder-drying or extrusion. In enzymatic derivatisation, degradation (reduction of the viscosity) and chemical modification of the amylo¬ pectin are effected by means of existing enzymatic sys¬ tems. The derivatisation is effected at different tempera¬ tures, according to the desired end product. The ordinary range of temperature which is used is 20-45°C, but tempe¬ ratures up to 180°C are possible. The invention will be described in more detail in the following Examples. Example 1 Production of microtubers with inserted antisense con¬ structs according to the invention The antisense constructs (see Figs 4, 5 and 6) are transferred to Agrobacterium tumefaciens LBA 4404 by the "freeze-thawing" method (An et al, 1988). The transfer to potato tissue is carried out according to a modified pro¬ tocol from Rocha-Sosa et al (1989). Leaf discs from potato plants cultured in vitro are incubated in darkness on a liquid MS-medium (Murashige & Skoog; 1962) with 3% saccharose and 0.5% MES together with 100 μl of a suspension of recombinant Agrobacterium per 10 ml medium for two days. After these two days the bacte- ria are killed. The leaf discs are transferred to a solid medium for callus induction and incubated for 4-6 weeks, depending on the growth of callus. The solid medium is composed as follows: MS + 3% saccarose 2 mg/1 zeatin riboside 0.02 mg/1 "NAA" 0.02 mg/1 "GAg" 500 mg/1 "Claforan" 50 mg/1 kanamycin 0.25% "Gellan" Subsequently the leaf discs are transferred to a medium having a different composition of hormones, com¬ prising: MS + 3% saccharose 5 mg/1 "NAA" 0.1 mg/1 "BAP" 500 mg/1 "Claforan" 50 mg/1 kanamycin 0.25% "Gellan" The leaf discs are stored on this medium for about 4 weeks, whereupon they are transferred to a medium in which the "Claforan" concentration has been reduced to 250 mg/1. If required, the leaf discs are then moved to a fresh medium every 4 or 5 weeks. After the formation of sprouts, these are cut away from the leaf discs and trans¬ ferred to an identical medium. The condition that the antisense construct has been transferred to the leaf discs is first checked by analys¬ ing leaf extracts from the regenerated sprouts in respect of glucuronidase activity by means of the substrates described by Jefferson et al (1987). The activity is demonstrated by visual assessment. Further tests of the expression of the antisense con¬ structs and the transfer thereof to the potato genome are carried out by southern and northern hybridisation accord¬ ing to Maniatis et al (1981). The number of copies of the antisense constructs that has been transferred is deter- mined by southern hybridisation. When it has been established that the antisense con¬ structs have been transferred to and expressed in the potato genome, the testing of the expression on protein level begins. The testing is carried out on microtubers which have been induced in vitro on the transformed sprouts, thereby avoiding the necessity of waiting for the development of a complete potato plant with potato tubers. Stem pieces of the potato sprouts are cut off at the nodes and placed on a modified MS medium. There they form microtubers after 2-3 weeks in incubation in darkness at 19°C (Bourque et al, 1987). The medium is composed as fol¬ lows: MS + 6% saccharose 2.5 mg/1 kinetin 2.5 mg/1 "Gellan" The effect of the antisense constructs on the func- tion of the GBSS gene in respect of the activity of the GBSS protein is analysed by means of electrophoresis on polyacrylamide gel (Hovenkamp-Hermelink et al, 1987). Starch is extracted from the microtubers and analysed regarding the presence of the GBSS protein. In a poly- acrylamide gel, the GBSS protein forms a distinct band at 60 kD, when the GBSS gene functions. If the GBSS gene is not expressed, i.e. when the antisense GBSS gene is fully expressed so that the formation of GBSS protein is inhi¬ bited, no 60 kD band can be seen on the gel. The composition of the starch, i.e. the proportion of amylose to amylopectin, is determined by a spectrophoto- metric method according to Hovenkamp-Hermelink et al (1988), the content of each starch component being deter¬ mined on the basis of a standard graph. Example 2 Extraction of amylopectin from amylopectin potato. Potato whose main starch component is amylopectin, below called amylopectin potato, modified in a genetically engineered manner according to the invention, is grated, thereby releasing the starch from the cell walls. The cell walls (fibres) are separated from fruit juice and starch in centrifugal screens (centrisiler). The fruit juice is separated from the starch in two steps, viz. first in hydrocyclones and subsequently in specially designed band-type vacuum filters. Then a finishing refining is carried out in hydro¬ cyclones in which the remainder of the fruit juice and fibres are separated. The product is dried in two steps, first by predrying on a vacuum filter and subsequently by final drying in a hot-air current. Example 3 Chemical derivatisation of amylopectin Amylopectin is sludged in water to a concentration of 20-50%. The pH is adjusted to 10.0-12.0 and a quatenary ammonium compound is added in such a quantity that the end product obtains a degree of substitution of 0.004-0.2. The reaction temperature is set at 20-45°C. When the reac¬ tion is completed, the pH is adjusted to 4-8, whereupon the product is washed and dried. In this manner the cationic starch derivative 2-hydroxy-3-trimethyl ammonium propyl ether is obtained. Example 4 Chemical derivatisation of amylopectin Amylopectin is sludged in water to a water content of 10-25% by weight. The pH is adjusted to 10.0-12.0, and a quatenary ammonium compound is added in such a quan¬ tity that the end product obtains a degree of substitution of 0.004-0.2. The reaction temperature is set at 20-45°C. When the reaction is completed, the pH is adjusted to 4-8. The end product is 2-hydroxy-3-trimethyl ammonium propyl ether. Example 5 Chemical derivatisation of amylopectin Amylopectin is sludged in water to a concentration of 20-50% by weight. The pH is adjusted to 5.0-12.0, and sodium hypochlorite is added so that the end product obtains the desired viscosity. The reaction temperature is set at 20-45°C. When the reaction is completed, the pH is adjusted to 4-8, whereupon the end product is washed and dried. In this manner, oxidised starch is obtained. Example 6 Physical derivatisation of amylopectin Amylopectin is sludged in water to a concentration of 20-50% by weight, whereupon the sludge is applied to a heated cylinder where it is dried to a film. 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F. and Sambrook, J., 1982, Molecular Cloning, A Laboratory Handbook, Cold Spring Harbor Laboratory Press, Cold Spring Harbor - Bourque, J. E., Miller, J. C. and Park, W. D., 1987, In Vitro Cellular & Development Biology 23(5):381-386 - Hovenkamp-Hermelink, J. H. M., Jacobsen, E., Ponstein, A. S., Visser, R. G. F., Vos-Scheperkeuter, G. H., Bijmolt, E. W., de Vries, J. N. , Witholt, B. J. & Feenstra, W. J., 1987, Theor. Appl. Genet. 75:217-221 - Hovenkamp-Hermelink, J. H. M. , de Vries, J. N., Adamse, P., Jacobsen, E., Witholt, B. and Feenstra, W. J., 1988, Potato Research 31:241-246 - Modified starches: Properties and use D. B. Wurzburg - Bevan, M. W., 1984. Nucleic Acids Res. 12:8711-8721. SEQ ID No. 1 Sequenced molecule: genomic DNA Name: GBSS gene fragment from potato Length of sequence: 342 bp TGCATGTTTC CCTACATTCT ATTTAGAATC GTGTTGTGGT GTATAAACGT 50 TGTTTCATAT CTCATCTCAT CTATTCTGAT TTTGATTCTC TTGCCTACTG 100 TAATCGGTGA TAAATGTGAA TGCTTCCTTT CTTCTCAGAA ATCAATTTCT 150 GTTTTGTTTT TGTTCATCTG TAGCTTATTC TCTGGTAGAT TCCCCTTTTT 200 GTAGACCACA CATCAC ATG GCA AGC ATC ACA GCT TCA CAC CAC 243 Ket Ala Ser lie T r Ala Ser His His 1 5 TTT GTG TCA AGA AGC CAA ACT TCA CTA GAC ACC AAA TCA ACC 285 ?he Val Ser Arg Ser Gin Thr Ser Leu ASΌ Thr Lys Ser Thr 10 15 20 TTG TCA CAG ATA GGA CTC AGG AAC CAT ACT CTG ACT CAC AAT 327 Leu Ser Gin lie Gly Leu Arg Asn His Thr Leu Thr His Asn 25 30 35 GGT TTA AGG GCT GTT 342 Gly Leu Arg Ala Val 40 SEQ ID No. 2 Sequenced molecule: genomic DNA Name: GBSS gene fragment from potato Length of sequence: 2549 bp AAC AAG CTT GAT GGG CTC CAA TCA ACA ACT AAT ACT AAG GTA 42 Asn Lys Leu ASD Gly Leu Gin Ser Thr Thr Asn Thr Lys Val 45 * 50 55 ACA CCC AAG ATG GCA TCC AGA ACT GAG ACC AAG AGA CCT GGA 84 Thr Pro Lys Met Ala Ser Arg Thr Glu Thr Lys Arg Pro Gly 60 65 70 TGC TCA GCT ACC ATT GTT TGT GGA AAG GGA ATG AAC TTG ATC 126 Cys Ser Ala Thr lie Val Cys Gly Lys Gly Met Asn Leu He 75 80 TTT GTG GGT ACT GAG GTT GGT CCT TGG AGC AAA ACT GGT GGA 168 Phe Val Gly Thr Glu Val Gly Pro Trr> Ser Lys Thr Gly Gly 85 90 95 CTA GGT GAT GTT CTT GGT GGA CTA CCA CCA GCC CTT GCA 207 Leu Gly ASΌ Val Leu Gly Gly Leu Pro Pro Ala Leu Ala 100 " 105 110 GTAAGTC77T CTTTCATTTG GTTACCTACT CATTCATTAC TTATTTTGTT 257 TAGTTAGTT? CTACTGCATC AGTCTTTTTA TCATTTAG GCC CGC GGA 304 Ala Arg Gly CAT CGG GTA ATG ACA ATA TCC CCC CGT TAT GAC CAA TAC AAA 346 His Arc Val Met. Thr He Ser Pro Arg Tyr ASΌ Gin Tyr Lys 115 ' 120 12 * 5 GAT GCT TGG GAT ACT GGC GTT GCG GTT GAG GTACATCTTC 386 ASΌ Ala T ASΌ Thr Gly Val Ala Val Glu 13C " ' 135 CTATATTGA7 ACGGTACAAT ATTGTTCTCT TACATTTCCT GATTCAAGAA 436 TGTGATCATC TGCAG GTC AAA GTT GGA GAC AGC ATT GAA ATT GTT 481 Val Lys Val Gly ASΌ Ser He Glu He Val 140 145 CGT TTC TTT CAC TGC TAT AAA CGT GGG GTT GAT CGT GTT TTT 523 Arg ?he ?he His Cys Tyr Lys Arg Gly Val Asp Arg Val ?he 15: 155 160 —3 n.-. - w.-i li-ϊ-..Λ GTAAGCATAΓ Val AΞ His P e V.~ :e leu TATGATTATG AATCCGTCCT GAGGGATACG CAGAACAGGT CATTTTGAGT 610 ATCTTTTAAC TCTACTGGTG CTTTTACTCT TTTAAG GTT TGG GGC AAA 658 Val Trp Gly Lys 175 ACT GGT TCA AAA ATC TAT GGC CCC AAA GCT GGA CTA GAT TAT 700 Thr Gly Ser Lys He Tyr Gly Pro Lys Ala Gly Leu Asp Tyr 180 185 CTG GAC AAT GAA CTT AGG TTC AGC TTG TTG TGT CAA 736 Leu ASΌ Asn Glu Leu Arg Phe Ser Leu Leu Cys Gin 190 * 195 200 GTAAGTTAGT TACTCTTGAT TTTTATGTGG CATTTTACTC TTTTGTCTTT 786 AATCGTTTTT TTAACCTTGT TTTCTCAG GCA GCC CTA GAG GCA CCT 832 Ala Ala Leu Glu Ala Pro 205 AAA GTT TTG AAT TTG AAC AGT AGC AAC TAC TTC TCA GGA CCA 874 Lys Val Leu Asn Leu Asn Ser Ser Asn Tyr Phe Ser Gly Pro 210 215 220 TAT G GTAATTAACA CATCCTAGTT TCAGAAAACT CCTTACTATA 918 Tyr G TCATTGTAGG TAATCATCTT TATTTTGCCT ATTCCTGCAG GA GAG GAT S66 ly Glu ASΌ 225 GTT CTC TTC ATT GCC AAT GAT TGG CAC ACA GCT CTC ATT CCT 1008 Val Leu Phe He Ala Asn Aso Tro His Thr Ala Leu He Pro 230 * * 235 TGC TAC TTG AAG TCA ATG TAC CAG TCC AGA GGA ATC TAC TTG 1050 Cys Tyr Leu Lys Ser Met Tyr Gin Ser Arg Gly He Tyr Leu 240 245 250 AAT GCC AAG GTAAAATTTC TTTGTATTCA CTCGATTGCA 1089 Asn Ala Lys 255 CGTTACCCTG CAAATCAGTA AGGTTGTATT AATATATGAT AAATTTCACA 1139 TTGCCTCCAG GTT GCT TTC TGC ATC CAT AAC ATT GCC TAC CAA 1182 Val Ala Phe Cys He His Asn He Ala Tyr Gin 260 265 GGT CGA TTT TCT TTC TCT GAC TTC CCT CTT CTC AAT CTT CCT 1224 Gly Arc Phe Ser ?he Ser Aso Phe Pro Leu Leu Asn Leu Pro 270 * 275 2S0 .-iCJ ~~ - 3 ;e: :-". "~~ m. 2 3 1313 AGTAAATTGA GTTTTTAAAA TTTTGCAGAT ATGAG AAG CCT GTT AAG 1360 Lys Pro Val Lys 295 GGT AGG AAA ATC AAC TGG ATG AAG GCT GGG ATA TTA GAA TCA 1402 Gly Arg Lys He Asn Trp Met Lys Ala Gly He Leu Glu Ser 300 305 310 CAT AGG GTG GTT ACA GTG AGC CCA TAC TAT GCC CAA GAA CTT 1444 His Arg Val Val Thr Val Ser Pro Tyr Tyr Ala Gin Glu Leu 315 320 325 GTC TCT GCT GTT GAC AAG GGA GTT GAA TTG GAC AGT GTC CTT 1486 Val Ser Ala Val ASΌ Lys Gly Val Glu Leu Asp Ser Val Leu 330 335 340 CGT AAG ACT TGC ATA ACT GGG ATT GTG AAT GGC ATG GAT ACA 1528 Arg Lys Thr Cys He Thr Gly He Val Asn Gly Met Asp Thr 345 350 CAA GAG TGG AAC CCA GCG ACT GAC AAA TAC ACA GAT GTC AAA 1570 Gin Glu Trp Asn Pro Ala Thr Asp Lys Tyr Thr Asp Val Lys 355 360 365 TAC GAT ATA ACC ACT GTAAGATAAG ATTTTTCCGA CTCCAGTATA 1615 Tyr ASΌ He Thr Thr 37 * 0 TACTAAAT7A TTTTGTATGT TTATGAAATT AAAGAGTTCT TGCTAATCAA 1665 AATCTCTA7A CAG GTC ATG GAC GCA AAA CCT TTA CTA AAG GAG 1708 Val Met Asp Ala Lys Pro Leu Leu Lys Glu 375 380 GCT CTT CAA GCA GCA GTT GGC TTG CCT GTT GAC AAG AAG ATC 1756 Ala Leu Gin Ala Ala Val Gly Leu Pro Val ASΌ Lys Lys He 385 390 * 395 CCT TTG ATT GGC TTC ATC GGC AGA CTT GAG GAG CAG AAA GGT 1792 Pro Leu He Gly Phe He Gly Arg Leu Glu Glu Gin Lys Gly 400 405 410 TCA GAT ATT CTT GTT GCT GCA ATT CAC AAG TTC ATC GGA TTG 1834 Ser Aso He Leu Ala Val Ala He His Lys Phe He Gly Leu 415 420 425 GAT GTT CAA ATT GTA GTC CTT GTAAGTACCA AATGGACTCA 1875 so Val Gin He Val Val Leu 430 ΓGGTATCΓ T - *- ■ r— i. r— —• --, -. * -, — -'r——r-f-- r—r- -, -, -- ---■ /— - - •. —■--.r-, -, r-'r- -—r- -. • OΛtf i i i -ft-, I - t-. L-l Ib- -.L - ."- " . A- . v:AlL . VJ . 1925 ~ £ CAG GAG ATT GAA CAG CTC GAA GTG TTG TAC CCT AAC AAA GCT 2010 Gin Glu He Glu Gin Leu Glu Val Leu Tyr Pro Asn Lys Ala 445 450 AAA GGA GTG GCA AAA TTC AAT GTC CCT TTG GCT CAC ATG ATC 2052 Lys Gly Val Ala Lys Phe Asn Val Pro Leu Ala His Met He 455 460 465 ACT GCT GGT GCT GAT TTT ATG TTG GTT CCA AGC AGA TTT GAA 2094 Thr Ala Gly Ala Asp Phe Met Leu Val Pro Ser Arg Phe Glu 470 475 480 CCT TGT GGT CTC ATT CAG TTA CAT GCT ATG CGA TAT GGA ACA 2136 Pro Cys Gly Leu He Gin Leu His Ala Met Arg Tyr Gly Thr 435 490 495 GTAAGAACCA GAAGAGCTTG TACCTTTTTA CTGAGTTTTT AAAAAAAGAA 2186 TCATAAGACC TTGTTTTCCA TCTAAAGTTT AATAACCAAC TAAATGTTAC 2236 TGCAGCAAGC TTTTCATTTC TGAAAATTGG TTATCTGATT TTAACGTAAT 2286 CACATGTGAG TCAG GTA CCA ATC TGT GCA TCG ACT GGT GGA CTT 2330 Val Pro He Cys Ala Ser Thr Gly Gly Leu 500 505 GTT GAC ACT GTG AAA GAA GGC TAT ACT GGA TTC CAT ATG GGA 2372 Val Aso Thr Val Lys Glu Gly Tyr Thr Gly Phe His Met Gly 510 515 520 GCC TTC AAT GTT GAA GTATGTGATT TTACATCAAT TGTGTACTTG 2417 Ala Phe Asn Val Glu 525 TACATGGTCC ATTCTCGTCT TC-ATATACCC CTTGTTGCAT AAACATTAAC 2467 TTATTGCTTC TTGAATTTGG TTAG TGC GAT GTT GTT GAC CCA GCT 2512 Cys Aso Val Val Aso Pro Ala 530 GAT GTG CTT AAG ATA GTA ACA ACA GTT GCT AGA GCT C 2549 Aso Val leu Lys He Val Thr Thr Val Ala Arg Ala 535 540 SEQ ID No. 3 Sequenced molecule: genomic DNA Name: GBSS gene fragment from potato Length of sequence: 492 bp GAG CTC TCC TGG AAG GTAAGTGTGA ATTTGATAAT TTGCGTAGGT 45 Glu Leu Ser Trp Lys 565 ACTTCAGTTT GTTGTTCTCG TCAGCACTGA TGGATTCCAA CTGGTGTTCT 95 TGCAG GAA CCT GCC AAG AAA TGG GAG ACA TTG 127 Glu Pro Ala Lys Lys Trp Glu Thr Leu 570 575 CTA TTG GGC TTA GGA GCT TCT GGC AGT GAA CCC GGT GTT GAA 169 Leu Leu Gly Leu Gly Ala Ser Gly Ser Glu Pro Gly Val Glu 5B0 585 590 GGG GAA GAA ATC GCT CCA CTT GCC AAG GAA AAT GTA GCC ACT 211 Gly Glu Glu He Ala Pro Leu Ala Lys Glu Asn Val Ala Thr 595 600 605 CCT TAA ATGAGCTTTG GTTATCCTTG TTTCAACAAT AAGATCATTA 257 Pro ~~~~χ 606 AGCAAACGTA TTTACTAGCG AACTATGTAG AACCCTATTA TGGGGTCTCA 307 ATCATCTACA AAATGATTGG TTTTTGCTGG GGAGCAGCAG CATATAAGGC 357 TGTAAAATCC TGGTTAATGT TTTTGTAGGT AAGGGCTATT TAAGGTGGTG 07 TGGATCAAAG TCAATAGAAA ATAGTTATTA CTAACGTTTG CAACTAAATA 457 CTTAGTAATG TAGCATAAAT AATACTAGAA CTAGT 492 SEQ ID No. 4 Sequenced molecule: genomic DNA Name: Promoter for the GBSS gene from potato Length of sequence: 987 bp SEQ ID No, Sequenced molecule: genomic DNA Name: GBSS gene from potato Length of sequence: 4964 bp AAGCTTTAAC GAGATAGAAA ATTATGTTAC TCCGTTTTGT TCATTACTTA 50 ACAAATGCAA CAGTATCTTG TACCAAATCC TTTCTCTCTT TTCAAACTTT 100 TCTATTTGGC TGTTGACGGA GTAATCAGGA TACAAACCAC AAGTATTTAA 150 TTGACTCCTC CGCCAGATAT TATGATTTAT GAATCCTCGA AAAGCCTATC 200 CATTAAGTCC TCATCTATGG ATATACTTGA CAGTATCTTC CTGTTTGGGT 250 ATTTTTTTTT CCTGCCAAGT GGAACGGAGA CATGTTATGA TGTATACGGG 300 AAGCTCGTTA AAAAAAAATA CAATAGGAAG AAATGTAACA AACATTGAAT 350 GTTGTTTTTA ACCATCCTTC CTTTAGCAGT GTATCAATTT TGTAATAGAA 400 CCATGCATCT CAATCTTAAT ACTAAAATGC AACTTAATAT AGGCTAAACC 450 AAGATAAAGT AATGTATTCA ACCTTTAGAA TTGTGCATTC ATAATTAGAT 500 CTTGTTTGTC GTAAAAAATT AGAAAATATA TTTACAGTAA TTTGGAATAC 550 AAAGCTAAGG GGGAAGTAAC TAATATTCTA GTGGAGGGAG GGACCAGTAC 600 CAGTACCTAG ATATTATTTT TAATTACTAT AATAATAATT TAATTAACAC 650 GAGACATAGG AATGTCAAGT GGTAGCGTAG GAGGGAGTTG GTTTAGTTTT 700 TTAGATACTA GGAGACAGAA CCGGACGGCC CATTGCAAGG CCAAGTTGAA 750 GTCCAGCCGT GAATCAACAA AGAGAGGGCC CATAATACTG TCGATGAGCA 800 TTTCCCTATA ATACAGTGTC CACAGTTGCC TTCTGCTAAG GGATAGCCAC 850 CCGCTATTCT CTTGACACGT GTCACTGAAA CCTGCTACAA ATAAGGCAGG 900 CACCTCCTCA TTCTCACTCA CTCACTCACA CAGCTCAACA AGTGGTAACT 950 TTTACTCATC TCCTCCAATT ATTTCTGATT TCATGCATGT TTCCCTACAT 1000 TCTATTATGA ATCGTGTTGT GGTGTATAAA CGTTGTTTCA TATCTCATCT 1050 CATCTATTCT GATTTTGATT CTCTTGCCTA CTGTAATCGG TGATAAATGT 1100 GAATGCTTCC TTTCTTCTCA GAAATCAATT TCTGTTTTGT TTTTGTTCAT 1150 CTGTAGCTTA TTCTCTGGTA GATTCCCCTT TTTGTAGACC ACACATCAC 1199 ATG GCA AGC ATC ACA GCT TCA CAC CAC TTT GTG TCA AGA AGC 1241 Met Ala Ser He Thr Ala Ser His His Phe Val Ser Arg Ser 1 5 10 CAA ACT TCA CTA GAC ACC AAA TCA ACC TTG TCA CAG ATA GGA 1283 Gin Thr Ser Leu Aso Thr Lys Ser Thr Leu Ser Gin He Gly 15 20 25 CTC AGG AAC CAT ACT CTG ACT CAC AAT GGT TTA AGG GCT GTT 1325 Leu Arg Asn His Thr Leu His Asn Gly Leu Arg Ala Val 30 35 40 AAC AAG CTT GAT GGG CTC CAA TCA ACA ACT AAT ACT AAG GTA 1367 Asn Lys Leu Aso Gly Leu Gin Ser Thr Thr Asn Thr Lys Val 45 * 50 55 ACA CCC AGA a ~ "τ GAG ACC AAG AGA CCT 1409 Thr Pre -ys Arg Glu Thr Lys Arg Pro Gly 65 70 TGC TCA GCT ACC ATT GTT TGT GGA AAG GGA ATG AAC TTG 1451 Cys Ser V Lys Gly Met Asn Leu ...e 80 T: ~ -J v » Λ i 1-jΛθ AGC AAA ACT GGT 1493 5 " > ~~ι -, - . Ser Lys Thr Gly 85 55 CTA GGT GAT GTT CTT GGT GGA CTA CCA CCA GCC CTT GCA 1532 Leu Gly Asp Val Leu Giv Gly Leu Pro Pro Ala Leu Ala 100 * 105 110 GTAAGTCTTT CTTTCATTTG GTTACCTACT CATTCATTAC TTATTTTGTT 1582 TAGTTAGTTT CTACTGCATC AGTCTTTTTA TCATTTAG GCC CGC GGA 1629 Ala Arg Gly CAT CGG GTA ATG ACA ATA TCC CCC CGT TAT GAC CAA TAC AAA 1671 His Arg Val Met Thr He Ser Pro Arg Tyr Asp Gin Tyr Lys 115 120 125 GAT GCT TGG GAT ACT GGC GTT GCG GTT GAG GTACATCTTC 1711 Asp Ala Trp Asp Thr Gly Val Ala Val Glu 130 135 CTATATTGAT ACGGTACAAT ATTGTTCTCT TACATTTCCT GATTCAAGAA 1761 TGTGATCATC TGCAG GTC AAA GTT GGA GAC AGC ATT GAA ATT GTT 1806 Val Lys Val Gly ASΌ Ser He Glu He Val 140 145 CGT TTC TTT CAC TGC TAT AAA CGT GGG GTT GAT CGT GTT TTT 1848 Arg Phe Phe His Cys Tyr Lys Arg Gly Val Aso Arg Val Phe 150 155 160 GTT GAC CAC CCA ATG TTC TTG GAG AAA GTAAGCATAT 1885 Val Asp His Pro Met Phe Leu Glu Lys 165 170 TATGATTATG AATCCGTCCT GAGGGATACG CAGAACAGGT CATTTTGAGT 1935 ATCTTTTAAC TCTACTGGTG CTTTTACTCT TTTAAG GTT TGG GGC AAA 1983 Val Tro Gly Lys 175 ACT GGT TCA AAA ATC TAT GGC CCC AAA GCT GGA CTA GAT TAT 2025 Thr Gly Ser Lys He Tyr Gly Pro Lys Ala Gly Leu Asp Tyr 180 185 CTG GAC AAT GAA CTT AGG TTC AGC TTG TTG TGT CAA 2061 Leu Asp Asn Glu Leu Arg Phe Ser Leu Leu Cys Gin 190 195 200 GTAAGTTAGT TACTCTTGAT TTTTATGTGG CATTTTACTC TTTTGTCTTT 2111 AATCGTTTTT TTAACCTTGT TTTCTCAG GCA GCC CTA GAG GCA CCT 2157 Ala Ala Leu Glu Ala Pro 205 AAA GTT TTG AAT TTG AAC AGT AGC AAC TAC TTC TCA GGA CCA 2199 Lys Val Leu Asn Leu Asn Ser Ser Asn Tyr Phe Ser Gly Pro 210 215 220 TAT G GTAATTAACA CATCCTAGTT TCAGAAAACT CCTTACTATA 2243 Tyr G TCATTGTAGG TAATCATCTT TATTTTGCCT ATTCCTGCAG GA GAG GAT 2291 ly Glu Asp 225 GTT CTC TTC ATT GCC AAT GAT TGG CAC ACA GCT CTC ATT CCT 2333 Val Leu Phe He Ala Asn ASΌ Trp His Thr Ala Leu He Pro 230 235 TGC TAC TTG AAG TCA ATG TAC CAG TCC AGA GGA ATC TAC TTG 2375 Cys Tyr Leu Lys Ser Met Tyr Gin Ser Arg Gly He Tyr Leu 240 245 250 AAT GCC AAG GTAAAATTTC TTTGTATTCA CTCGATTGCA 2414 Asn Ala Lys 255 CGTTACCCTG CAAATCAGTA AGGTTGTATT AATATATGAT AAATTTCACA 2464 TTGCCTCCAG GTT GCT TTC TGC ATC CAT AAC ATT GCC TAC CAA 2507 Val Ala Phe Cys He His Asn He Ala Tyr Gin 260 265 GGT CGA TTT TCT TTC TCT GAC TTC CCT CTT CTC AAT CTT CCT 2549 Gly Arc Phe Ser Phe Ser Aso Phe Pro Leu Leu Asn Leu Pro 270 * 275 280 GAT GAA TTC AGG GGT TCT TTT GAT TTC ATT GAT GGG TAT 2588 Aso Glu Phe Arg Gly Ser Phe Aso Phe He ASΌ Gly Tyr 285 290 GTATTTATGC TTGAAATCAG ACCTCCAACT TTTGAAGCTC TTTTGATGCT 2638 AGTAAATTGA GTTTTTAAAA TTTTGCAGAT ATGAG AAG CCT GTT AAG 2685 Lys Pro Val Lys 295 GGT AGG AAA ATC AAC TGG ATG AAG GCT GGG ATA TTA GAA TCA 2727 Gly Arg Lys He Asn Tro Meύ Lys Ala Gly He Leu Glu Ser 300 305 310 CAT AGG GTG GTT ACA GTG AGC CCA TAC TAT GCC CAA GAA CTT 2769 His Arg Val Val Thr Val Ser Pro Tyr Tyr Ala Gin Glu Leu 315 320 325 GTC TCT GCT GTT GAC AAG GGA GTT GAA TTG GAC AGT GTC CTT 2811 Val Ser Ala Val Aso Lys Giv Val Glu Leu Aso Ser Val Leu 330 * 335 * 340 ^:;j Arc Lvs ~ -*- v 6 " ~ "" Λ ~" ~ "~ ~ 3"v ~ " ■ — V s " ----- ■" ."•• s- i;« --- -- ~ J- =. " ~ . ~ -1 CAA GAG TGG AAC CCA GCG ACT GAC AAA TAC ACA GAT GTC AAA 2895 Gin Glu Trp Asn Pro Ala Thr Asp Lys Tyr Thr Asp Val Lys 355 360 365 TAC GAT ATA ACC ACT GTAAGATAAG ATTTTTCCGA CTCCAGTATA 2940 Tyr Asp He Thr Thr 370 TACTAAATTA TTTTGTATGT TTATGAAATT AAAGAGTTCT TGCTAATCAA 2990 AATCTCTATA CAG GTC ATG GAC GCA AAA CCT TTA CTA AAG GAG 3033 Val Met Asp Ala Lys Pro Leu Leu Lys Glu 375 380 GCT CTT CAA GCA GCA GTT GGC TTG CCT GTT GAC AAG AAG ATC 3075 Ala Leu Gin Ala Ala Val Gly Leu Pro Val Asp Lys Lys He 385 390 395 CCT TTG ATT GGC TTC ATC GGC AGA CTT GAG GAG CAG AAA GGT 3117 Pro Leu He Gly Phe He Gly Arg Leu Glu Glu Gin Lys Gly 400 405 410 TCA GAT ATT CTT GTT GCT GCA ATT CAC AAG TTC ATC GGA TTG 3159 Ser Asp He Leu Ala Val Ala He His Lys Phe He Gly Leu 415 420 425 GAT GTT CAA ATT GTA GTC CTT GTAAGTACCA AATGGACTCA 3200 Asp Val Gin He Val Val Leu 430 TGGTATCTCT CTTGTTGAGT TTACTTGTGC CGAAACTGAA ATTGACCTGC 3250 TACTCATCCT ATGCATCAG GGA ACT GGC AAA AAG GAG TTT GAG 3293 Gly Thr Gly Lys Lys Glu Phe Glu 435 440 CAG GAG ATT GAA CAG CTC GAA GTG TTG TAC CCT AAC AAA GCT 3335 Gin Glu He Glu Gin Leu Glu Val Leu Tyr Pro Asn Lys Ala 445 450 AAA GGA GTG GCA AAA TTC AAT GTC CCT TTG GCT CAC ATG ATC 3377 Lys Gly Val Ala Lys Phe Asn Val Pro Leu Ala His Met He 455 460 465 ACT GCT GGT GCT GAT TTT ATG TTG GTT CCA AGC AGA TTT GAA 3419 Thr Ala Gly Ala Asp Phe Met Leu Val Pro Ser Arg Phe Glu 470 475 480 CCT TGT GGT CTC ATT CAG TTA CAT GCT ATG CGA TAT GGA ACA 3461 Pro Cys Gly Leu He Gin Leu His Ala Met Arg Tyr Gly Thr 455 490 495 GTAAGAACCA GAAGAGCTTG TACCTTTTTA CTGAGTTTTT AAAAAAAGAA 3511 TCATAAGACC TTGTTTTCCA TCTAAAGTTT AATAACCAAC TAAATGTTAC 3561 TGCAGCAA3C TTTTCATTTC TGAAAATTGG TTATCTGATT TTAACGTAAT 3611 CACATGTGAG TCAG GTA CCA ATC TGT GCA TCG ACT GGT GGA CTT 365 Val Pro He Cys Ala Ser Thr Gly Gly Leu 500 505 GTT GAC ACT GTG AAA GAA GGC TAT ACT GGA TTC CAT ATG GGA 369 Val Asp Thr Val Lys Glu Gly Tyr Thr Gly Phe His Met Gly 510 515 520 GCC TTC AAT GTT GAA GTATGTGATT TTACATCAAT TGTGTACTTG 374 Ala Phe Asn Val Glu 525 TACATGGTCC ATTCTCGTCT TGATATACCC CTTGTTGCAT AAACATTAAC 379 TTATTGCTTC TTGAATTTGG TTAG TGC GAT GTT GTT GAC CCA GCT 383 Cys Asp Val Val Asp Pro Ala 530 GAT GTG CTT AAG ATA GTA ACA ACA GTT GCT AGA GCT CTT GCA 387 Asp Val Leu Lys He Val Thr Thr Val Ala Arg Ala Leu Ala 535 540 545 GTC TAT GGC ACC CTC GCA TTT GCT GAG ATG ATA AAA AAT TGC 392 Val Tyr Gly Thr Leu Ala Phe Ala Glu Met He Lys Asn Cys 550 555 560 ATG TCA GAG GAG CTC TCC TGG AAG GTAAGTGTGA ATTTGATAAT 396 Met Ser Glu Glu Leu Ser Tro Lys 565 TTGCGTAGGT ACTTCAGTTT GTTGTTCTCG TCAGCACTGA TGGATTCCAA 401 CTGGTGTTCT TGCAG GAA CCT GCC AAG AAA TGG GAG ACA TTG 405 Glu Pro Ala Lys Lys Trp Glu Thr Leu 570 575 CTA TTG GGC TTA GGA GCT TCT GGC AGT GAA CCC GGT GTT GAA 409 Leu Leu Gly Leu Gly Ala Ser Gly Ser Glu Pro Gly Val Glu 580 585 59Q GGG GAA GAA ATC GCT CCA CTT GCC AAG GAA AAT GTA GCC ACT 414 Gly Glu Glu He Ala Pro Leu Ala Lys Glu Asn Val Ala Thr 595 600 605 CCT TAA ATGAGCTTTG GTTATCCTTG TTTCAACAAT AAGATCATTA 418 Pro ** ~~ 606 AGCAAACGTA TTTACTAGCG AACTATGTAG AACCCTATTA TGGGGTCTCA 423 ATCATCTACA AAATGATTGG TTTTTGCTGG GGAGCAGCAG CATATAAGGC 428 TGTAAAATCC TGGTTAATGT TTTTGTAGGT AAGGGCTATT TAAGGTGGTG 433 TGGATCAAAG TCAATAGAAA ATAGTTATTA CTAACGTTTG CAACTAAATA 438 AATACTAGAA CTAGTAGCTA ATATATATGC 443 -.. ι_.Λ-.ΛΛ. .......j -. . --.>». ■ -.i A - i-i. -..-_-. i -ι3 ' AGAAGTAATC AAATTCAAAT TAGTTGTTTG GTCATATGAA AGAAGCTGCC 46 AGGCTAACTT TGAGGAGATG GCTATTGAAT TTCAAAATGA TTATGTGAAA 46 ACAATGCAAC ATCTATGTCA ATCAACACTT AAATTATTGC ATTTAGAAAG 47 ATATTTTTGA GCCCATGACA CATTCATTCA TAAAGTAAGG TAGTATGTAT 47 GATTGAATGG ACTACAGCTC AATCAAAGCA TCTCCTTTAC ATAACGGCAC 48 TGTCTCTTGT CTACTACTCT ATTGGTAGTA GTAGTAGTAA TTTTACAATC 48 CAAATTGAAT AGTAATAAGA TGCTCTCTAT TTACTAAAGT AGTAGTATTA 49 TTCTTTCGTT ACTCTAAAGC AACAAAA 49

Claims: CLAIMS 1. Method of suppressing amylose formation in potato, c h a r a c t e r i s e d by genetically engi¬ neered modification of the potato by introducing into the genome of the potato tissue a gene construct comprising a fragment of the potato gene which codes for formation of granule-bound starch synthase (GBSS gene) inserted in the antisense direction, said fragment being selected among the fragments which essentially have the nucleotide sequences stated in SEQ ID No. 1, SEQ ID No. 2 and SEQ ID No. 3 together with a promoter selected among CaMV 35S, patatin I and the GBSS promoter. 2. Amylopectin-type native starch, c h a r a c ¬ t e r i s e d in that it has been obtained from potato which has been modified in a genetically engineered man¬ ner for suppressing formation of amylose-type starch. 3. Derivatised amylopectin-type starch, c h a r - a c t e r i s e d in that it is amylopectin-type starch extracted from potato which has been modified in a gene¬ tically engineered manner for suppressing formation of amylose-type starch, said amylopectin-type starch subse¬ quently being derivatised in a chemical, physical or enzymatic manner. 4. Fragment of the gene coding for granule-bound starch synthase (GBSS) in potato, said fragment being selected among the fragments which essentially have the nucleotide sequences stated in SEQ ID No. 1, SEQ ID No. 2 and SEQ ID No. 3. 5. Promoter for the gene for granule-bound starch synthase (GBSS) in potato, said promoter being tuber- specific and having essentially the nucleotide sequence stated in SEQ ID No. 4. 6. Gene coding for granule-bound starch synthase in potato (GBSS gene) having essentially the nucleotide sequence stated in SEQ ID No. 5. 7. Antisense construct for inhibiting expression of the gene for granule-bound starch synthase in potato, comprising a) a promoter, b) a fragment of the gene coding for granule-bound starch synthase inserted in the antisense direction, said fragment being selected among the fragments hav¬ ing essentially the nucleotide sequences stated in SEQ ID No. 1, SEQ ID No. 2 and SEQ ID No. 3. 8. Antisense construct as claimed in claim 7, c h a r a c t e r i s e d in that the promoter essen¬ tially has the sequence stated in SEQ ID No. 4. 9. Antisense construct as claimed in claim 7, c h a r a c t e r i s e d in that the promoter is select- ed among the CaMV 35S promoter and the patatin I promoter. 10. Vector comprising a fragment of the gene coding for granule-bound starch synthase (GBSS) in potato, said fragment being selected among the fragments having essen¬ tially the nucleotide sequences stated in SEQ ID No. 1, SEQ ID No. 2 and SEQ ID No. 3, and inserted in the anti¬ sense direction. 11. Vector comprising the antisense construct as claimed in any one of claims 7-9. 12. Cell of potato plant whose genome comprises the antisense construct as claimed in any one of claims 7-9. 13. Potato plant whose genome comprises the antisense construct as claimed in any one of claims 7-9. 14. Potato tubers whose genome comprises the antisense construct as claimed in any one of claims 7-9. 15. Seeds from potato plant, whose genome comprises the antisense construct as claimed in any one of claims 7-9. 16. Microtubers of potato, whose genome comprises the antisense construct as claimed in any one of claims 7-9.

Inventors: HOFVANDER PER, PERSSON PER T, TALLBERG ANNELI, WIKSTROEM OLLE, HOFVANDER, PER, PERSSON, PER, T., TALLBERG, ANNELI, WIKSTROEM, OLLE
Applicants: AMYLOGENE HB
Application year: 1991
Main classification: C12N9
IPC codes: A01H5, C08B30, C08B35, C12N5, C12N9, C12N15, C12P19