bluuebunny/crossref_metadata_2025_split huggingface dataset:
The promoter of the rice gene GOS2 is active in various different monocot tissues and binds rice nuclear factor ASF‐1
Authors: de Pater B. Sylvia , van der Mark Frits , Rueb Saskia , Katagiri Fumiaki , Chua Nam‐Hai , Schilperoort Rob A. , Hensgens Lambert A. M. 
Published: March 2003

SummaryA single copy gene has been isolated, termed GOS2, from rice. Sequence comparison revealed highly similar genes in mammals and yeast, indicating that GOS2 encodes an evolutionary conserved protein. GOS2 mRNA was detected in all tissues examined. When the upstream region was translationally fused to the reporter gene gusA it was found to drive expression in a variety of rice tissues and in cell suspensions of other monocot species following introduction by particle bombardment. Therefore, the GOS2 promoter is potentially useful for genetic engineering of monocots. A DNA‐binding activity from rice, termed rice ASF‐1, with similar binding specificity as the cloned tobacco transcription factor TGA‐1a, was found to bind to a TGACG sequence motif in the GOS2 promoter. Possible roles for rice ASF‐1 in the transcriptional activation of the GOS2 promoter are discussed.
Isolation and characterization of male flower cDNAs from maize
Authors: Wright Susan Y. , Suner Marie‐Marthe , Bell Philip J. , Vaudin Mark , Greenland Andrew J. 
Published: March 2003

SummaryDifferential screening of two libraries made from whole, immature maize tassels was used to isolate six cDNAs which show enhanced levels of expression in male flowers. MFS1, MFS2, MFS4, MFS10 and MFS18, which were isolated from a 5 cm tassel library, are expressed throughout tassel growth up until mature pollen is produced in the anthers. MFS14, which was isolated from a 10–12 cm tassel library, has a narrower window of expression associated with microsporogenesis and declines as mature pollen is produced. MFS18 mRNA accumulates in the glumes and in anther walls, paleas and lemmas of mature florets. MFS18 mRNA is particularly associated with the vascular bundle in the glumes and encodes a polypeptide of 12 kDa, rich in glycine, proline and serine that has similarities with other plant structural proteins. In contrast, MFS14 mRNA accumulates in the tapetum and encodes a polypeptide of 13 kDa that is rich in alanine. The MFS14 and MFS18 proteins are basic (isolectric points of 11.56 and 9.54, respectively) and both have hydrophobic N‐termini which display all the characteristics of signal peptides, indicating that these proteins may be secreted.
Protein phosphatase inhibitors activate anti‐fungal defence responses of soybean cotyledons and cell cultures
Authors: MacKintosh Carol , Lyon Gary D. , MacKintosh Robert W. 
Published: March 2003

SummaryThe application of a variety of structurally different protein phosphatase inhibitors (okadaic acid, acanthifolicin, microcystins, nodularin, tautomycin, calyculin A, cantharidin and endothall) to cut surfaces of soybean cotyledons (Glycine max L.) resulted in the production of isoflavonoid phytoalexins (plant defence compounds). Daidzein was the predominant isoflavonoid produced by soybean cotyledons in response to protein phosphatase inhibitors. In contrast, several isoflavonoid phytoalexins were seen after application of either an elicitor β‐glucan fraction isolated from yeast extract or hepta‐(1→3, 1→6)‐β‐glucoside which is the most potent elicitor‐active component isolated from the soybean pathogen Phytophthora megasperma f. sp. glycinea. Isoflavonoid production in response to either protein phosphatase inhibitors or elicitors reached a maximum after 20–24 h. The addition of protein phosphatase inhibitors to a soybean cell suspension culture induced the expression of phenylalanine ammonia‐lyase (PAL), the first enzyme in the isoflavonoid biosynthetic pathway. Induction of PAL activity was blocked by protein synthesis inhibitors, cycloheximide or anisomysin, and largely prevented by a protein kinase inhibitor, K252a. Another common response of plant cells to fungal elicitation, alkalinization of the soybean cell culture media, was induced within minutes in response to protein phosphatase inhibitors and was largely prevented by K252a.These studies suggest a direct role for phosphorylation in activation of plasma membrane ion flux(es), whereas the longer‐term effects of protein phosphatase inhibitors on isoflavonoid production and PAL expression could be due to either direct effects of increased protein phosphorylation, or the secondary consequences of other phosphorylation‐induced cellular changes. They also indicate that protein phosphatase inhibitors are likely to be of general use in investigating mechanisms of plant responses to environmental stimuli.
In situ hybridization localizes avocado sunblotch viroid on chloroplast thylakoid membranes and coconut cadang cadang viroid in the nucleus
Authors: Bonfiglioli Roderick G. , McFadden Geoffrey I. , Symons Robert H. 
Published: March 2003

SummaryViroids, small single‐stranded circular RNA molecules, are the smallest known infectious agents in Nature. The apparent inability of viroids to encode for proteins means that they must rely fully on host functions for their replication. The specific ultrastructural localization of viroids is fundamental to the determination of their replication strategies. In this paper the first in situ hybridization study to localize viroids within the cell at the electron microscope level is reported. Biotin‐labelled RNA probes were used with subsequent detection by gold‐labelled monoclonal anti‐biotin antibodies to localize avocado sunblotch viroid and coconut cadang cadang viroid. Avocado sunblotch viroid was located in chloroplasts, mostly on the thylakoid membranes of cells from infected leaves of avocado (Persea americana). In contrast, coconut cadang cadang viroid was located in the nucleolus and nucleoplasm of cells of infected leaves of oil palm (Elaeis guineensis), with a higher concentration in the nucleolus. The results provide insight on the potential host RNA polymerases involved in the replication of these two viroids.
Genetic length polymorphisms create size variation in proline‐rich proteins of the cell wall
Authors: Schmidt John Scott , Lindstrom Jon T. , Vodkin Lila O. 
Published: March 2003

SummaryTwo genes, Prp1 and Prp2, encode proline‐rich proteins that are found in different stages of developing seed coats, hypocotyls, and roots of soybeans (Glycine max (L.) Merr.). PRP1 is found in young seed coats and PRP2 is found later during seed dessication. In some soybean varieties, both proteins are smaller as determined by immunoblotting seed coat proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was found that Prp1 and Prp2 genes are linked to each other by testing seed coat protein extracts from an F2 population of a cross between the cultivar Richland, which exhibits the larger PRP proteins, and Blackhawk, which has the smaller PRP proteins. The Prp1 and Prp2 genes were separated by approximately 13% recombination. Simultaneous expression of soluble PRP2 polypeptides in the maternal seed coat and underlying aleurone layer of the embryo was found. The molecular basis for the size difference between the two varieties was examined using polymerase chain reaction to isolate the Prp genes from Blackhawk, the variety that exhibited the smaller proteins. Both of the genes from Blackhawk contained length polymorphisms that result in omission of some of the repeat units (pro pro val tyr lys) from the proteins. In Prp1, there were two separate deletions in different parts of the gene, each being two tandem repeats in length. In Prp2, there was only one deletion of two tandem repeats. These deletions occur within the coding regions in a manner that conserves the reading frame. The results are the first description of genetic variation in cell wall proteins and its molecular basis. The nature of these genetic length polymorphisms indicates that the basic repeat unit structure is conserved and that the proline‐rich proteins of the cell wall tolerate loss or gain of integral numbers of repeat units.
A self‐stabilizing Ac derivative and its potential for transposon tagging
Authors: Schmitz Gregor , Theres Klaus 
Published: March 2003

SummaryWith the goal of developing a self‐stabilizing transposon tagging system, a derivative of the maize transposable element Ac (Ds303) harbouring a deletion between bp 246 and 736 has been introduced into tomato (Lycopersicon esculentum) by Agrobacterium tumefaciens‐mediated transformation. The deletion removes the major transcription start site, 84 bp of the putative Ac promoter and part of the untranslated leader. Transpositions from the T‐DNA, where Ds303 was inserted between the mannopine synthase 1′ promoter and the GUS gene, were observed in four independent transgenic plants analysed. After transposition the transposed Ds303 elements were stably integrated in the genome and could not transactivate a tester Ds element. However, somatic and germinal transpositions of the transposed Ds303 elements occurred in the presence of a transposase source.
Complementary deletions in expressed potato U2snRNA gene variants support the hypothesis that stem—loop IIb is dispensable for splicing
Authors: Brown John W.S. , Simpson Craig G. , Clark Gillian P. , Waugh Robble 
Published: March 2003

SummaryA polymerase chain reaction (PCR) strategy designed to amplify DNA sequences between closely linked U2snRNA genes has generated extensive coding and 5′ regulatory sequence information on the potato U2snRNA multigene family. Two of the U2snRNA coding sequences isolated differed substantially from normal U2snRNAs by containing both complementary deletions and regions of novel sequence. However, sequences such as Sm‐binding sites and loops of stem—loops III and IV, which are some of the most highly conserved regions in U2snRNA, remain highly conserved in these genes. The complementary deletions would effectively remove stem—loop IIb which has been shown in yeast to be unnecessary for pre‐mRNA splicing. Transcripts from one of the genes have been detected by reverse transcriptase‐PCR (RT‐PCR) in total RNA. These novel U2snRNA genes represent the first reported example of naturally occurring structural variants and provide support for the proposed non‐essential role of U2snRNA stem—loop IIb.
Metabolism of 3‐ and 4‐phosphorylated phosphatidylinositols in stomatal guard cells of Commelina communis L.
Authors: Parmar Paroo N. , Brearley Charles A. 
Published: March 2003

Within the plant kingdom the stomatal guard cell is presented as a model system of inositol 1,4,5‐trisphosphate [Ins(1,4,5)P3]‐mediated signal transduction. Despite this it is only recently that the phosphoinositide components of animal signal transduction pathways have been identified in stomatal guard cells. Interestingly, stomatal guard cells contain both 3‐ and 4‐phosphorylated phosphatidylinositols though their relative contributions to signalling remain undefined. An appraisal of the routes of synthesis and rates of turnover of these phosphatidylinositols would appear timely as the in vivo biosynthesis of these components is a much neglected facet of the phosphoinositide‐mediated signalling paradigm as purported to apply to plants.A non‐equilibrium [32P]Pi labelling strategy and enzymic and chemical dissection of labelled phosphatidylinositols have been used to address not only the route of synthesis but also the rates of turnover of phosphatidylinositols in stomatal guard cells of Commelina communis L.The specific activity of the ATP pool of isolated guard cells was found to increase over a 4 h period when labelled from [32P]Pi. In separate experiments, isolated guard cells were labelled over a 40–240 min period, their lipids extracted, deacylated and resolved by HPLC. Glycerophosphoinositol phosphate (GroPInsP) and glycerophosphoinositol bisphosphate (GroPInsP2) peaks were desalted and enzymically cleaved with alkaline phosphatase and human erythrocyte ghosts, respectively. The monoester phosphate in phosphatidylinositol 4‐monophosphate (PtdIns4P) accounted for 90–97% of the [32P]Pi label while the 4‐ and 5‐monoester phosphates of phosphatidylinositol 4,5‐bisphosphate [PtdIns(4,5)P2] accounted for typically 39% and 61% respectively. Therefore, the evidence is consistent with synthesis of PtdIns(4,5)P2 by successive 4‐ and 5‐phosphorylation of phosphatidylinositol (PtdIns). This study therefore represents the first report of the pathway of the synthesis of 4‐ and 5‐phosphorylated phosphatidylinositols in a single defined hormone‐responsive plant cell type.The monoester phosphate in phosphatidylinositol 3‐monophosphate (PtdIns3P) accounted for 83–95% of the 32P label. It was not possible, however, to determine the route of synthesis of phosphatidylinositol 3,4‐bisphosphate [PtdIns(3,4)P2] owing to the rapid attainment of equilibrium between the 3‐ and 4‐monoester phosphates of PtdIns(3,4)P2, each containing approximately 50% of the label at just 40 min of labelling. Turnover of PtdIns3P was quicker than that of PtdIns4P. Similarly, turnover of PtdIns(3,4)P2 was quicker than that of PtdIns(4,5)P2, and in mass terms PtdIns(3,4)P2 appeared to predominate over PtdIns(4,5)P2. By analogy with animal systems, in which signalling molecules such as PtdIns(4,5)P2 show considerable basal turnover, the evidence presented is consistent with signalling roles for PtdIns3P and PtdIns(3,4)P2 in addition to those previously indicated for PtdIns(4,5)P2 in stomatal guard cells.
Cell cycle‐regulated histone gene expression in synchronized plant cells
Authors: Reichheld Jean‐Philippe , Sonobe Seiji , Clément Bernadette , Chaubet Nicole , Gigot Claude 
Published: March 2003

SummaryThe regulation of histone gene expression during the cell cycle has been studied in a synchronized tobacco (BY2) cell suspension. Maximal expression was found in S phase but unlike other eukaryotic organisms the amount of histone mRNA was not coupled to DNA synthesis. Using aphidicolin as an inhibitor of DNA synthesis either before or at mid‐S phase an accumulation of histone mRNAs was found in the absence of any DNA synthesis which was not due to a stabilization of the mRNAs but to actual control at the transcriptional level. At the completion of unperturbed or delayed S phase, histone mRNAs were selectively degraded by a post‐transcriptional mechanism requiring de novo transcription.
Feedback inhibition of fatty acid synthesis in tobacco suspension cells
Authors: Shintani David K. , Ohlrogge John B. 
Published: March 2003

SummaryThe flux through many metabolic pathways is regulated through feedback inhibition on regulatory enzymes by endproducts of the pathway. Whether feedback inhibition occurs in fatty acid synthesis in plants has been investigated. The addition of exogenous oleic acid, in the form of oleoyl‐Tween (Tween‐18:1) caused a three‐ to fivefold decrease in the rate of [1‐14C]acetate incorporation into tobacco suspension cell fatty acids. The decrease in acetate incorporation occurred rapidly upon addition of Tween‐18:1 and appeared to be specific for fatty acid synthesis. In order to elucidate possible regulatory steps involved in the feedback regulation of fatty acid synthesis in plant cells, tobacco cell acyl‐ACP intermediates were analyzed using a combination of [1‐14C]acetate labeling and immunoblot analysis. Within 30 min of exogenous lipid addition, acetyl‐ACP increased and long chain acyl‐ACP decreased, whereas medium chain acyl‐ACP levels remained constant. These acyl‐ACP profiles observed during the feedback inhibition were those predicted to occur under conditions where the flux through fatty acid synthesis is decreased due to limiting levels of malonyl‐CoA and therefore indicated that acetyl‐CoA carboxylase (ACCase) was centrally involved in the feedback regulation of fatty acid synthesis. Immunoblot analysis showed that ACCase protein levels did not change during the feedback inhibition, indicating that the feedback inhibition of fatty acid synthesis in plant cells occurs through biochemical or post‐translational modification of ACCase and possibly other fatty acid synthesis enzymes.
Expression of the early nodulin, ENOD40, in soybean roots in response to various lipo‐chitin signal molecules
Authors: Minami Eiichi , Kouchi Hiroshi , Cohn Jonathan R. , Ogawa Tomoya , Stacey Gary 
Published: March 2003

SummaryThe lipo‐chitin (LCO) nodulation signal (nod signal) purified from Bradyrhizobium japonicum induced nodule primordia on soybean (i.e. Glycine soja) roots. These primordia were characterized by a bifurcated vascular connection, cortical cell division, and the accumulation of mRNA of the early nodulin gene, ENOD40. A chemically synthesized LCO identical in structure to the Nod signal purified from B. japonicum cultures showed the same activity when inoculated on to soybean roots. Surprisingly, synthetic LCO or chitin pentamer, inactive in inducing root hair curling (HAD) or cortical cell division (NOI) in G. soja, induced the transient accumulation of ENOD40 mRNA. In roots inoculated with such LCO, ENOD40 mRNA was abundant at 40 h after inoculation but decreased to the background levels 6 days after inoculation. In contrast, nod signals active in inducing HAD and NOI induced high levels of ENOD40 accumulation at 40 h and 6 days after inoculation. In situ hybridization analysis showed that ENOD40 mRNA accumulated in the pericycle of the vascular bundle at 24 h after root inoculation with nod signal. At 6 days post‐inoculation with nod signal, ENOD40 expression was seen in dividing subepidermal cortical cells. These results provide morphological and molecular evidence that nodule induction in soybean in response to purified or synthetic nod signal is similar, if not identical, to nodule formation induced by bacterial inoculation. Surprisingly, ENOD40 mRNA accumulation occurs in response to non‐specific chitin signals. This suggests that, in the case of ENOD40, nodulation specificity is not determined at the level of initial gene expression.
Distribution of tobamovirus movement protein in infected cells and implications for cell‐to‐cell spread of infection
Authors: Padgett Hal S. , Epel Bernard L. , Kahn Theodore W. , Heinlein Manfred , Watanabe Yuichiro , Beachy Roger N. 
Published: March 2003

SummaryThe intercellular and intracellular distribution of the movement protein (MP) of the Ob tobamovirus was examined in infected leaf tissues using an infectious clone of Ob in which the MP gene was translationally fused to the gene encoding the green fluorescent protein (GFP) of Aequorea victoria. In leaves of Nicotiana tabacum and N. benthamiana, the modified virus caused fluorescent infection sites that were visible as expanding rings. Microscopy of epidermal cells revealed subcellular patterns of accumulation of the MP:GFP fusion protein which differed depending upon the radial position of the cells within the fluorescent ring. Punctate, highly localized fluorescence was associated with cell walls of all of the epidermal cells within the infection site, and apparently represents association of the fusion protein with plasmodesmata; furthermore, fluorescence was retained in cell walls purified from infected leaves. Within the brightest region of the fluorescent ring, the MP:GFP was observed in irregularly shaped inclusions in the cortical regions of infected cells. Fluorescent filamentous structures presumed to represent association of MP:GFP with microtubules were observed, but were distributed differently within the infection sites on the two hosts. Within cells containing filaments, a number of fluorescent bodies, some apparently streaming in cytoplasmic strands, were also observed. The significance of these observations is discussed in relation to MP accumulation, targeting to plasmodesmata, and degradation.
CLA1, a novel gene required for chloroplast development, is highly conserved in evolution
Authors: Mandel M. Alejandra , Feldmann Kenneth A. , Herrera‐Estrella Luis , Rocha‐Sosa Mario , León Patricia 
Published: March 2003

SummaryAn albino mutant designated cla1‐1 (for ‘cloroplastos alterado’, or ‘altered chloroplasts’) has been isolated from a T‐DNA‐generated library of Arabidopsis thaliana. In cla11 plants, chloroplast development is arrested at an early stage. cla1‐1 plants behave like wild‐type in their capacity to etiolate and produce anthocyanins indicating that the light signal transduction pathway seems to be unaffected. Genetic and molecular analyses show that the disruption of a single gene, CLA1, by the T‐DNA insertion is responsible for the mutant phenotype. RNA expression patterns indicate that CLA1 is positively regulated by light and that it has different effects on the steady‐state RNA levels of some nuclear‐ and chloroplast‐encoded photosynthetic genes. Although the specific function of the CLA1 gene is still unknown, it encodes a novel protein conserved in evolution between photosynthetic bacteria and plants which is essential for chloroplast development in Arabidopsis.
Detailed description of four YAC contigs representing 17 Mb of chromosome 4 of Arabidopsis thaliana ecotype Columbia
Authors: Schmidt Renate , West Joanne , Cnops Gerda , Love Karina , Balestrazzi Alma , Dean Caroline 
Published: March 2003

SummaryThe detailed arrangement of 563 YAC clones comprising four contigs covering ∼17 Mbp of chromosome 4 is presented. YAC clones were positioned relative to each other and to markers by taking into account marker and end fragment hybridization data and the sizes of all YAC clones. This analysis made it possible to estimate physical distances between the majority of chromosome 4 markers. It also identified a relatively large number of YAC clones containing chimaeric inserts. The YAC contig map of the Columbia ecotype presents an important resource for map‐based cloning experiments, rapid mapping of DNA sequences and large‐scale genomic sequencing programs.
Phytochrome‐induced intercellular signalling activates cab::luciferase gene expression
Authors: Bischoff Friedrich , Millar Andrew J. , Kay Steve A. , Furuya Masaki 
Published: March 2003

SummaryThe phytochrome‐induced expression pattern of the chlorophyll a/b binding protein (cab) gene was studied using a cab2::luciferase reporter transgene in the tobacco cotyledon. The role of developmentally regulated competence, cooperativity among cells and signal propagation was investigated by red‐light microbeam irradiation of distinct areas of the cotyledon. Even with a minimal fluence, the response was not restricted to the irradiated cells. Following irradiation of the cotyledon base, the luciferase activity revealed a robust propagation of activating signals to areas that had not received a light stimulus. The acropetal outspread formed distinct expression patterns depending on the site of the irradiation. The combination of imaging luciferase activity in living seedlings and microbeam microscopy provides significant experimental evidence of how cellular light perception and intercellular signalling contribute to the cab gene expression pattern.