Project description:Global transcriptional profiling has been successfully used to identify genes and regulatory pathways in secondary cell wall thickening. A systematic microarray assay of secondary cell wall development along stem maturation in Medicago truncatula was conducted to identify genes and pathways that are involved in lignin/cellulose biosynthesis of secondary wall development.
Project description:Cellulose from plant biomass is the largest renewable energy resource of carbon fixed from the atmosphere, which can be converted into fermentable sugars for production into ethanol. However, the cellulose present as lignocellulosic biomass is embedded in a hemicellulose and lignin matrix from which it needs to be extracted for efficient processing. Here, we show that expression of an Arabidopsis transcription factor SHINE (SHN) in rice, a model for the grasses, causes a 34% increase in cellulose and a 45% reduction in lignin content.
Project description:Cellulose from plant biomass is the largest renewable energy resource of carbon fixed from the atmosphere, which can be converted into fermentable sugars for production into ethanol. However, the cellulose present as lignocellulosic biomass is embedded in a hemicellulose and lignin matrix from which it needs to be extracted for efficient processing. Here, we show that expression of an Arabidopsis transcription factor SHINE (SHN) in rice, a model for the grasses, causes a 34% increase in cellulose and a 45% reduction in lignin content. Rice genotypes expressing the Arabidopsis SHN2 gene hereafter called rice AtSHN lines were used in this study. Progenies of three independent AtSHN lines were grown in controlled growth chambers. For all analyses, six plants were used for each of the two transgenic lines and WT. For total RNA isolation, rice leaf tissue of WT and AtSHN lines was used. Samples were hybridized to the rice Affymetrix GeneChip.
Project description:Phosphate starvation/sufficient rice seedling, root or shoot Pi-starvation or Pi-sufficient stresses responsible rice genes, including previously unannotated genes were identified by Illumina mRNA-seq technology. 53 million reads from Pi-starvation or Pi-sufficient root or shoot tissues were uniquely mapped to the rice genome, and these included 40574 RAP3 transcripts in root and 39748 RAP3 transcripts in shoot. We compared our mRNA-seq expression data with that from Rice 44K oligomicroarray, and about 95.5% (root) and 95.4% (shoot) transcripts supported by the array were confirmed expression both by the array and by mRNA-seq, Moreover, 11888 (root) and 11098 (shoot) RAP genes which were not supported by array, were evidenced expression with mRNA-seq. Furthermore, we discovered 8590 (root) and 8193 (shoot) previously unannotated transcripts upon Pi-starvation and/or Pi-sufficient.
Project description:Drought is a major environmental constraint affecting physiological, biochemical and molecular changes of crops, causing loss in crop productivities. Understanding the molecular mechanisms of drought tolerance is important for crop biotechnology. Here, we report that the rice (Oryza sativa) homeodomain-leucine zipper class IV transcription factor gene, Rice outermost cell-specific gene 10 (Roc10), improves drought tolerance and grain yield by increasing lignin accumulation in ground tissues of rice plants. Overexpression of Roc10 significantly enhanced drought tolerance of transgenic rice plants at the vegetative stages of growth with highly effective photosystem and reduction of water loss rate as compared with non-transgenic control and RNAi plants. More importantly, Roc10 overexpression plants had higher drought tolerance at the reproductive stage of growth with higher grain yield over controls under field-drought conditions. We identified downstream and putative target genes of Roc10 by using RNA-seq and ChIP-seq data of rice shoots. Roc10 overexpression elevated the expression levels of lignin biosynthetic genes in shoots with a concomitant increase in accumulation of lignin. The overexpression and RNAi lines showed opposite patterns of lignin accumulation. The Roc10 is mainly expressed in the outer cell layers including epidermis and vasculature of shoots that coincides with areas of increased lignification. Furthermore, the Roc10 was found to directly bind to the promoter of PEROXIDASEN/PEROXIDASE38, a key gene in lignin biosynthesis. Together, our findings suggested that the Roc10 confers drought stress tolerance by enhancing lignin biosynthesis in ground tissues of rice plants.
Project description:Drought is a major environmental constraint affecting physiological, biochemical and molecular changes of crops, causing loss in crop productivities. Understanding the molecular mechanisms of drought tolerance is important for crop biotechnology. Here, we report that the rice (Oryza sativa) homeodomain-leucine zipper class IV transcription factor gene, Rice outermost cell-specific gene 10 (Roc10), improves drought tolerance and grain yield by increasing lignin accumulation in ground tissues of rice plants. Overexpression of Roc10 significantly enhanced drought tolerance of transgenic rice plants at the vegetative stages of growth with highly effective photosystem and reduction of water loss rate as compared with non-transgenic control and RNAi plants. More importantly, Roc10 overexpression plants had higher drought tolerance at the reproductive stage of growth with higher grain yield over controls under field-drought conditions. We identified downstream and putative target genes of Roc10 by using RNA-seq and ChIP-seq data of rice shoots. Roc10 overexpression elevated the expression levels of lignin biosynthetic genes in shoots with a concomitant increase in accumulation of lignin. The overexpression and RNAi lines showed opposite patterns of lignin accumulation. The Roc10 is mainly expressed in the outer cell layers including epidermis and vasculature of shoots that coincides with areas of increased lignification. Furthermore, the Roc10 was found to directly bind to the promoter of PEROXIDASEN/PEROXIDASE38, a key gene in lignin biosynthesis. Together, our findings suggested that the Roc10 confers drought stress tolerance by enhancing lignin biosynthesis in ground tissues of rice plants.
Project description:The within-tree variation in wood properties constitutes an exceptional model to study the mechanisms that adjust the different biosynthetic pathways providing substrates with the massive and variable demands of different biosynthetic reactions of cell wall polymers. Although a few genes have been reported as differentially expressed in differentiating compression wood compared to normal or opposite wood, the expression of a larger set of genes is expected to change due the broad range of features that distinguish this reaction wood. By combining the construction of different cDNA libraries with microarray analyses, using samples from different Pinus pinaster provenances collected in different years and geographic locations, we have identified a total of 496 genes that change their expression during differentiation of compression wood (331 up-regulated and 165 down-regulated compared to opposite wood). Consistent with the well-known structural and chemical characteristics of compression wood, a large number of genes involved in the biosynthesis of cell wall components were shown to be up-regulated during compression wood differentiation, including genes involved in synthesis of cellulose, hemicellulose, lignin and lignans. In particular, further analysis of a set of these genes involved in providing S-adenosylmethionine, ammonium recycling, lignin and lignans biosynthesis showed parallel expression profiles to levels of lignin accumulation in cells undergoing xylogenesis in vivo and in vitro. The comparative transcriptomic analysis of compression and opposite wood formation in this work have revealed a broad spectrum of coordinated transcriptional modulation of biosynthetic reactions for different cell wall polymers associated to within-tree variations in softwood structure and composition. In particular, it suggest the occurrence of a mechanism that modulates at transcriptional level genes encoding enzymes involved in S-adenosylmethionine synthesis and ammonium assimilation with coniferyl alcohol demand for lignin and lignan synthesis, as a key metabolic requirement in cells undergoing lignification. Two-condition experiment including dye-swap experiments, Compression Differentiating Xylem vs. Opposite Differentiating Xylem. Biological replicates: 4 compression xylem, 4 opposite xylew, harvested from four different individual pine trees. Two replicates per array.
Project description:The within-tree variation in wood properties constitutes an exceptional model to study the mechanisms that adjust the different biosynthetic pathways providing substrates with the massive and variable demands of different biosynthetic reactions of cell wall polymers. Although a few genes have been reported as differentially expressed in differentiating compression wood compared to normal or opposite wood, the expression of a larger set of genes is expected to change due the broad range of features that distinguish this reaction wood. By combining the construction of different cDNA libraries with microarray analyses, using samples from different Pinus pinaster provenances collected in different years and geographic locations, we have identified a total of 496 genes that change their expression during differentiation of compression wood (331 up-regulated and 165 down-regulated compared to opposite wood). Consistent with the well-known structural and chemical characteristics of compression wood, a large number of genes involved in the biosynthesis of cell wall components were shown to be up-regulated during compression wood differentiation, including genes involved in synthesis of cellulose, hemicellulose, lignin and lignans. In particular, further analysis of a set of these genes involved in providing S-adenosylmethionine, ammonium recycling, lignin and lignans biosynthesis showed parallel expression profiles to levels of lignin accumulation in cells undergoing xylogenesis in vivo and in vitro. The comparative transcriptomic analysis of compression and opposite wood formation in this work have revealed a broad spectrum of coordinated transcriptional modulation of biosynthetic reactions for different cell wall polymers associated to within-tree variations in softwood structure and composition. In particular, it suggest the occurrence of a mechanism that modulates at transcriptional level genes encoding enzymes involved in S-adenosylmethionine synthesis and ammonium assimilation with coniferyl alcohol demand for lignin and lignan synthesis, as a key metabolic requirement in cells undergoing lignification. Two-condition experiment including dye-swap experiments, Compression Differentiating Xylem vs. Opposite Differentiating Xylem. Biological replicates: 4 compression xylem, 4 opposite xylew, harvested from four different individual pine trees. Two replicates per array.