High-temperature stress, like any abiotic stress, impairs the physiology and development of plants, including the stages of seed setting and ripening. We used the Affymetrix 22K Barley1 GeneChip microarray to investig...High-temperature stress, like any abiotic stress, impairs the physiology and development of plants, including the stages of seed setting and ripening. We used the Affymetrix 22K Barley1 GeneChip microarray to investigate the response of developing barley （Hordeum vulgare） seeds, termed caryopses, after 0.5, 3, and 6 h of heat stress exposure; 958 induced and 1122 repressed genes exhibited spatial and temporal expression patterns that provide a detailed insight into the caryopses＇ early heat stress responses. Down-regulation of genes related to storage compound biosynthesis and cell growth provides evidence for a rapid impairment of the caryopsis＇ development. Increased levels of sugars and amino acids were indicative for both production of compatible solutes and feedback-induced accumulation of substrates for storage compound biosynthesis. Metadata analysis identified embryo and endosperm as primary locations of heat stress responses, indicating a strong impact of short-term heat stress on central developmental functions of the caryopsis. A comparison with heat stress responses in Arabidopsis shoots and drought stress responses in barley caryopses identified both conserved and presumably heat- and caryopsis-specific stress-responsive genes. Summarized, our data provide an important basis for further investigation of gene functions in order to aid an improved heat tolerance and reduced losses of yield in barley as a model for cereal crops.展开更多
Work with cereals （barley and wheat） and a legume （Medicago truncatula） has established thioredoxin h （Trx h） as a central regulatory protein of seeds. Trx h acts by reducing disulfide （S-S） groups of diverse ...Work with cereals （barley and wheat） and a legume （Medicago truncatula） has established thioredoxin h （Trx h） as a central regulatory protein of seeds. Trx h acts by reducing disulfide （S-S） groups of diverse seed proteins （storage proteins, enzymes, and enzyme inhibitors）, thereby facilitating germination. Early in vitro protein studies were complemented with experiments in which barley seeds with Trx h overexpressed in the endosperm showed accelerated germination and early or enhanced expression of associated enzymes （α-amylase and pullulanase）. The current study extends the transgenic work to wheat. Two approaches were followed to alter the expression of Trx h genes in the endosperm： （1） a hordein promoter and its protein body targeting sequence led to overexpression of Trx hS, and （2） an antisense construct of Trx h9 resulted in cytosolic underexpression of that gene （Arabidopsis designation）. Underexpression of Trx h9 led to effects opposite to those observed for overexpression Trx h5 in barley--retardation of germination and delayed or reduced expression of associated enzymes. Similar enzyme changes were observed in developing seeds. The wheat lines with underexpressed Trx showed delayed preharvest sprouting when grown in the greenhouse or field without a decrease in final yield. Wheat with overexpressed Trx h5 showed changes commensurate with earlier in vitro work： increased solubility of disulfide proteins and lower aUergenicity of the gliadin fraction. The results are further evidence that the level of Trx h in cereal endosperm determines fundamental properties as well as potential applications of the seed.展开更多
A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis, cDNA sequences were generated from developing nasturtium （Tropaeolum ma...A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis, cDNA sequences were generated from developing nasturtium （Tropaeolum majus） seeds, which produce large amounts of non-fucosylated xyloglucan as a seed storage polymer. In addition to known xyloglucan biosynthetic genes, a previously uncharacterized putative xyloglucan galactosyltransferase was iden- tified. Analysis of an Arabidopsis thaliana mutant line defective in the corresponding ortholog （AT5G62220） revealed that this gene shows no redundancy with the previously characterized xyloglucan galactosyltransferase, MUR3, but is required for galactosyl-substitution of xyloglucan at a different position. The gene was termed XLT2 for Xyloglucan L-side chain galactosylTransferase position 2. It represents an enzyme in the same subclade of glycosyltransferase family 47 as MUR3. A double mutant defective in both MUR3 （mur3.1） and XLT2 led to an Arabidopsis plant with xyloglucan that consists essentially of only xylosylated glucosyl units, with no further substitutions.展开更多
ABA is one of the 5 phytohormones in higher plants, which is also the most important hormone that regulates higher plants in response to environmental stress, by ABA signal transduction. Understanding ABA signal trans...ABA is one of the 5 phytohormones in higher plants, which is also the most important hormone that regulates higher plants in response to environmental stress, by ABA signal transduction. Understanding ABA signal transduction at the molecular level is crucial to biology and ecology, and rational breeding complied with corresponding eco-environmental changes. Great advancements have taken place over the past 10 years by application of the Arabidopsis experimental system. Many components involved in ABA signal transduction have been isolated and identified and a clear overall picture of gene expression and control for this transduction has become an accepted fact. On the basis of the work in our laboratory, in conjunction with the data available at the moment, the authors have attempted to integrate ABA signal transduction pathways into a common one and give some insights into the relationship between ABA signal transduction and other hormone signal transduction pathways, with an emphasis upon the ABA signal transduction during higher plant seed development. A future challenge in this field is that different experimental systems are applied and various receptors and genes need to be characterized through the utilization of microarray chips.展开更多
文摘High-temperature stress, like any abiotic stress, impairs the physiology and development of plants, including the stages of seed setting and ripening. We used the Affymetrix 22K Barley1 GeneChip microarray to investigate the response of developing barley （Hordeum vulgare） seeds, termed caryopses, after 0.5, 3, and 6 h of heat stress exposure; 958 induced and 1122 repressed genes exhibited spatial and temporal expression patterns that provide a detailed insight into the caryopses＇ early heat stress responses. Down-regulation of genes related to storage compound biosynthesis and cell growth provides evidence for a rapid impairment of the caryopsis＇ development. Increased levels of sugars and amino acids were indicative for both production of compatible solutes and feedback-induced accumulation of substrates for storage compound biosynthesis. Metadata analysis identified embryo and endosperm as primary locations of heat stress responses, indicating a strong impact of short-term heat stress on central developmental functions of the caryopsis. A comparison with heat stress responses in Arabidopsis shoots and drought stress responses in barley caryopses identified both conserved and presumably heat- and caryopsis-specific stress-responsive genes. Summarized, our data provide an important basis for further investigation of gene functions in order to aid an improved heat tolerance and reduced losses of yield in barley as a model for cereal crops.
文摘Work with cereals （barley and wheat） and a legume （Medicago truncatula） has established thioredoxin h （Trx h） as a central regulatory protein of seeds. Trx h acts by reducing disulfide （S-S） groups of diverse seed proteins （storage proteins, enzymes, and enzyme inhibitors）, thereby facilitating germination. Early in vitro protein studies were complemented with experiments in which barley seeds with Trx h overexpressed in the endosperm showed accelerated germination and early or enhanced expression of associated enzymes （α-amylase and pullulanase）. The current study extends the transgenic work to wheat. Two approaches were followed to alter the expression of Trx h genes in the endosperm： （1） a hordein promoter and its protein body targeting sequence led to overexpression of Trx hS, and （2） an antisense construct of Trx h9 resulted in cytosolic underexpression of that gene （Arabidopsis designation）. Underexpression of Trx h9 led to effects opposite to those observed for overexpression Trx h5 in barley--retardation of germination and delayed or reduced expression of associated enzymes. Similar enzyme changes were observed in developing seeds. The wheat lines with underexpressed Trx showed delayed preharvest sprouting when grown in the greenhouse or field without a decrease in final yield. Wheat with overexpressed Trx h5 showed changes commensurate with earlier in vitro work： increased solubility of disulfide proteins and lower aUergenicity of the gliadin fraction. The results are further evidence that the level of Trx h in cereal endosperm determines fundamental properties as well as potential applications of the seed.
文摘A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis, cDNA sequences were generated from developing nasturtium （Tropaeolum majus） seeds, which produce large amounts of non-fucosylated xyloglucan as a seed storage polymer. In addition to known xyloglucan biosynthetic genes, a previously uncharacterized putative xyloglucan galactosyltransferase was iden- tified. Analysis of an Arabidopsis thaliana mutant line defective in the corresponding ortholog （AT5G62220） revealed that this gene shows no redundancy with the previously characterized xyloglucan galactosyltransferase, MUR3, but is required for galactosyl-substitution of xyloglucan at a different position. The gene was termed XLT2 for Xyloglucan L-side chain galactosylTransferase position 2. It represents an enzyme in the same subclade of glycosyltransferase family 47 as MUR3. A double mutant defective in both MUR3 （mur3.1） and XLT2 led to an Arabidopsis plant with xyloglucan that consists essentially of only xylosylated glucosyl units, with no further substitutions.
基金the National Key Basic Research Development Program (Grant No. 2000018605 and 1999011708) the Major Research Plan of NSFC (Grant No. 90102012) and the Chinese National Outstanding Youth Fund (Grant No. 40025106)
文摘ABA is one of the 5 phytohormones in higher plants, which is also the most important hormone that regulates higher plants in response to environmental stress, by ABA signal transduction. Understanding ABA signal transduction at the molecular level is crucial to biology and ecology, and rational breeding complied with corresponding eco-environmental changes. Great advancements have taken place over the past 10 years by application of the Arabidopsis experimental system. Many components involved in ABA signal transduction have been isolated and identified and a clear overall picture of gene expression and control for this transduction has become an accepted fact. On the basis of the work in our laboratory, in conjunction with the data available at the moment, the authors have attempted to integrate ABA signal transduction pathways into a common one and give some insights into the relationship between ABA signal transduction and other hormone signal transduction pathways, with an emphasis upon the ABA signal transduction during higher plant seed development. A future challenge in this field is that different experimental systems are applied and various receptors and genes need to be characterized through the utilization of microarray chips.
