Transcription profiling of rice dwarf mutant Fukei71
Ontology highlight
ABSTRACT: Microarray analysis was used to identify candidate genes involved in the formation of hydroxycinnamoyl-arabinoxylan (AX) and secondary cell walls in rice. Gene expression in the internode pith parenchyma of Fukei71 (F71), the rice dwarf mutant that accumulates large amounts of hydroxycinnamoyl-AX in its pith parenchyma cells, was compared with the gene expression in wild-type pith parenchyma cells. Gene expression in wild-type whole internodes containing cells with thickened secondary cell walls, such as vascular and cortical fiber cells, was compared to the gene expression in wild-type internode pith parenchyma cells without any secondary cell walls.
Project description:Stem internodes of grasses function in mechanical support, transport, and, in some species are a major sink organ for carbon in the form of cell wall polymers. To establish the rice elongating internode as a model for secondary cell wall development, we conducted cell wall composition, proteomic and metabolomic analyses of the second rice internode at booting stage. We measured major secondary cell wall components along eight segments of an elongating internode. Cellulose, lignin, and xylose increase as a percentage of cell wall material from the younger to the older internode segments, indicating active cell wall synthesis. With the whole elongating internode, we measured peptides via liquid-chromatography mass spectrometry (LC-MS) following trypsin digestion of size fractionated proteins. This identified a total of 3249 protein groups with at least two unique peptides, including many glycosyltransferases, acyltransferases, glycohyrolases, cell wall-localized proteins, and protein kinases that have or may have functions in cell wall biosynthesis or remodeling. In addition, GO over-representation analysis and KO pathway analysis indicate many proteins involved in biosynthetic processes, especially the synthesis of secondary metabolites such as phenylpropanoids, flavonoids, and tepenoids. Therefore, we also used LC-MS to measure methanol-extracted secondary metabolites from the whole internode at the elongation stage and three post-elongation stages, and from leaf and root at the second post-elongation stage. The results indicate secondary metabolites in stems are distinct from those of roots and leaves, and show different profiles during stem development. This study fills a void of knowledge of proteomics and metabolomics data for grass stems, especially of rice, and provides baseline knowledge for more detailed studies of cell wall synthesis and other biological processes during internode development. This and future work is aimed at optimizing stem development and cell wall composition of grasses to improve agronomic properties and biofuel production.
Project description:In order to investigate the gene expression profile related to rice internode growth under different nitrogen management practices, Agilent two color microarray chips were used to profile the differentially expressed genes of rice first internode between two nitrogen management. A rice cultivars Yin-Jing-Ruan-Zhan was used as material. First basal internode of YJRZ was taken at 30 days after transplanting, and RNA was extracted for microarray assay. Materials from OPT were label by Cy5 and FFP by Cy3.
Project description:An AGCVIII kinase (Dw2) regulates sorghum stem internode growth, but the underlying mechanism and signaling network are unknown. Here we provide evidence that mutation of Dw2 reduces cell proliferation in internode intercalary meristems, inhibits endocytosis, and alters the distribution of heteroxylan and mixed linkage glucan in cell walls. Phosphoproteomic analysis showed that Dw2 signaling influences the phosphorylation of proteins involved in lipid signaling (PLDδ), endomembrane trafficking, hormone, light and receptor signaling, and photosynthesis. Together
Project description:In plants, secondary wall thickenings play important roles in various biological processes, although the factors regulating these processes remain to be characterized. We show that expression of chimeric repressors derived from NAC SECONDARY WALL THICKENINGS PROMOTING FACTOR1 (NST1) and NST2 in Arabidopsis resulted in an anther dehiscence defect due to loss of secondary wall thickening in anther endothecium. Plants with double, but not single, T-DNA-tagged lines for NST1 and NST2, had the same anther-indehiscent phenotype as transgenic plants that expressed the individual chimeric repressors, indicating that NST1 and NST2 are redundant in regulating secondary wall thickening in anther walls. The activity of the NST2 promoter was particularly strong in anther tissue, while that of the NST1 promoter was detected in various tissues in which lignified secondary walls develop. Ectopic expression of NST1 or NST2 induced ectopic thickening of secondary walls in various above-ground tissues. Epidermal cells with ectopic thickening of secondary walls had structural features similar to those of tracheary elements. However, among genes involved in the differentiation of tracheary elements, only those related to secondary wall synthesis were clearly upregulated. None of the genes involved in programmed cell death was similarly affected. Our results suggest NAC transcription factors as possible regulators of secondary wall thickening in various tissues. Experiment Overall Design: Total RNA was extracted from rosette leaves of two independent 2-week-old T1 plants over-expressing NST1 driven by 35S promoter and the whole transcriptome was compared with that of wild-type plant.
Project description:Arabidopsis, when grown under short day conditions (16 hours dark, 8 hours light, 22oC) develop extensive secondary thickened hypocotyls with both a vascular and cork cambium (Chaffey et al, 2002, Phys. Plant., 114:594-600). It has been found that once secondary xylem development is completed within the Arabidopsis hypocotyls, it closely resembles the structure of the wood of angiosperm trees (Chaffey et al, 2002, Phys. Plant., 114:594-600). We can utilise this model Arabidopsis tree to identify genes that are important for secondary cell wall formation in xylem cells and therefore important for wood development. Columbia plants were grown for 3 months under short day conditions and secondary thickened hypocotyls were snap-frozen in liquid nitrogen. RNA was isolated from these hypocotyls and submitted to NASC for probing against the ATH1-121501 full GeneChip.
Project description:Arabidopsis, when grown under short day conditions (16 hours dark, 8 hours light, 22oC) develop extensive secondary thickened hypocotyls with both a vascular and cork cambium (Chaffey et al, 2002, Phys. Plant., 114:594-600). It has been found that once secondary xylem development is completed within the Arabidopsis hypocotyls, it closely resembles the structure of the wood of angiosperm trees (Chaffey et al, 2002, Phys. Plant., 114:594-600). We can utilise this model Arabidopsis tree to identify genes that are important for secondary cell wall formation in xylem cells and therefore important for wood development. Columbia plants were grown for 3 months under short day conditions and secondary thickened hypocotyls were snap-frozen in liquid nitrogen. RNA was isolated from these hypocotyls and submitted to NASC for probing against the ATH1-121501 full GeneChip. Experiment Overall Design: 2 samples
Project description:Plant height is a critical constituent of plant architecture. Rice (Oryza sativa) plants have the potential to undergo rapid internodal elongation, which determines plant height. A number of physiological studies have proved that gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. Plant LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin responsiveness during the internode elongation process by down-regulation of the gibberellin biosynthetic gene, ent-KAURENE OXIDASE (OsKO2). Leaf tissues of 6-week-old LRK1 060615 transgenic rice and control 9311 rice (10 plants each) were selected.
Project description:Despite the economic importance of grasses as food, feed and energy crops, little is known about the genes that control their cell wall synthesis, assembly and remodelling. Here we provide a detailed transcriptome analysis that allowed the identification of genes involved in grass cell wall biogenesis. Differential gene-expression profiling, using maize oligonucleotide arrays, was used to identify genes differentially expressed between an elongating internode, containing cells exhibiting primary cell wall synthesis, and an internode that had just ceased elongation and in which many cells were depositing secondary cell wall material. This is one of only few studies specifically aimed at the identification of cell wall-related genes in grasses. Analysis identified new candidate genes for a role in primary and secondary cell wall-related processes in grasses. The results suggest that many proteins involved in cell wall-related processes during normal development are also recruited during defence-related cell wall remodelling events. The data presented provide a platform for future studies in which candidate genes can be tested for involvement in cell wall processes through forward and reverse genetic-based approaches, contributing towards a better understanding of cell wall biogenesis and its regulation in grasses. The experiment consisted of six biological replicates (internode 9 and internode 13 were harvested from six maize plants). Dye-swaps were performed (in 3 slides, internode 9 RNA was labelled with Cy3 and internode 13 RNA was labelled with Cy5; in 3 other slides, internode 13 RNA was labelled with Cy3 and internode 9 RNA was labelled with Cy5).
Project description:Plant height is a critical constituent of plant architecture. Rice (Oryza sativa) plants have the potential to undergo rapid internodal elongation, which determines plant height. A number of physiological studies have proved that gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. Plant LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin responsiveness during the internode elongation process by down-regulation of the gibberellin biosynthetic gene, ent-KAURENE OXIDASE (OsKO2).