Project description:Identification and sequencing of lignin biosynthesis, lignification and lignin pathway control in the orphan grain crop, Digitaria exilis
Project description:ra15-06_oxmyc4 - atmyc4 overexpression in arabidopsis (ws) - identification of new transcription factors for lignin biosynthesis - Compare the gene transcription in the mature stem of Arabidopsis wild type (ws) and AtMYC4 overexpressors (inws background)
Project description:Our previous studies, comparing russeted vs. waxy apple skin, highlighted a MYeloBlastosys (Myb) transcription factor (MdMYB52-like), which displayed a correlation with genes associated to the suberization process. The present article aims to assess its role and function in the suberization process. Phylogenetic analyses and research against Arabidopsis thaliana MYBs database were first performed and the tissue specific expression of MdMYB52-like was investigated using RT-qPCR. The function of MdMYB52-like was further investigated using Agrobacterium-mediated transient overexpression in Nicotiana benthamiana leaves. An RNA-Seq analysis was performed to highlight differentially regulated genes in response MdMYB52-like. Transcriptomic data were supported by analytical chemistry and microscopy. A massive decreased expression of photosynthetic and primary metabolism pathways was observed with a concomitant increased expression of genes associated with phenylpropanoid and lignin biosynthesis, cell wall modification and senescence. Interestingly key genes involved in the synthesis of suberin phenolic components were observed. The analytical chemistry displayed a strong increase in the lignin content in the cell walls during MdMYB52 expression. More specifically, an enrichment in G-Unit lignin residues was observed, supporting transcriptomic data as well as previous work describing the suberin phenolic domain as a G-unit enriched lignin-like polymer. The time-course qPCR analysis revealed that the observed stress response, might be explain by this lignin biosynthesis and by a possible programmed senescence triggered by MdMYB52-like. The present work supports a crucial regulatory role for MdMYB52 in the biosynthesis of the suberin phenolic domain and possibly in the fate of suberized cells in russeted apple skins.
Project description:Sugarcane is an important crop in tropical regions of the world, producing a very large biomass and accumulating large amounts of sucrose in the stem. In this study, we present the first report of transcript profiling using the GeneChip Sugarcane Genome Array. We have identified transcripts that are differentially expressed in the sugarcane stem during development by expression profiling using the array and total RNA derived from three disparate stem tissues (meristem, internodes 1-3; internode 8; internode 20) from four replicates of the sugarcane variety Q117 grown in the field. We have identified 119 transcripts that were highly differentially expressed with stem development and have characterised members of the cellulose synthase (CesA) and cellulose synthase-like (Csl) gene families which displayed coordinated expression during stem development. In addition, we determined that many other transcripts involved in cell wall metabolism and lignification were also co-expressed with members of the CesA and Csl gene families, offering additional insights into the dynamics of primary and secondary cell wall synthesis in the developing sugarcane stem. Keywords: stem development profile
Project description:Inflorescence stems of 20 Arabidopsis thaliana mutants, each mutated in a single gene of the lignin biosynthetic pathway (PAL1 , PAL2, C4H, 4CL1, 4CL2, CCoAOMT1, CCR1, F5H1, COMT and CAD6, two mutant alleles each) were analyzed by microarrays.
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.