Project description:The phytohormone cytokinin plays a significant role in nearly all aspects of plant growth and development. Cytokinin signaling has primarily been studied in the dicot model Arabidopsis, with relatively little work done in monocots, which include rice (Oryza sativa) and other cereals of agronomic importance. The cytokinin signaling pathway is a phosphorelay comprised of the histidine kinase receptors (HKs), the authentic histidine phosphotransfer proteins (AHPs), and the type-B Response Regulators (ARRs). Two negative regulators of cytokinin signaling have been identified: the type-A ARRs, which are cytokinin primary response genes, and the pseudo histidine phosphotransfer proteins (PHPs), which lack the His residue required for phosphorelay. Here, we describe the role of the PHP genes from rice. Phylogenic analysis indicates that the PHPs are generally first found in the genomes of gymnosperms and that they arose independently in monocots and dicots. Consistent with this, the three rice PHPs fail to complement an Arabidopsis php mutant (ahp6). Disruption of the three PHPs results in a molecular phenotype consistent with these elements acting as negative regulators of basal cytokinin signaling, including the constitutive up-regulation of a number of type-A RR and cytokinin oxidase genes. The triple php mutant affects multiple aspects of rice growth and development, including shoot morphology, panicle architecture and seed fill. However, in contrast to Arabidopsis, disruption of the rice PHPs does not affect root vascular patterning, suggesting that while many aspects of key signaling networks are conserved between monocots and dicots, the molecular components regulating some processes are distinct.
Project description:A transcription factor CYTOKININ-RESPONSIVE GATA FACTOR 1 (CGA1) regulates chloroplast development in rice (Oryza sativa) through modifying the expression of important nuclear expressed, chloroplast localized genes. A transcriptome analysis was done in wild type plants and transgenic rice over-expressing this OsCGA1 to identify the set of genes with altered expression.
Project description:A time course gene expression profiling of rice treated with various plant hormones (abscisic acid, gibberelin, auxin, brassinosteroid, cytokinin and jasmonic acid) was performed to obtain an overall signature of the rice transcriptome in response to each phytohormone.
Project description:A transcription factor CYTOKININ-RESPONSIVE GATA FACTOR 1 (CGA1) regulates chloroplast development in rice (Oryza sativa) through modifying the expression of important nuclear expressed, chloroplast localized genes. A transcriptome analysis was done in wild type plants and transgenic rice over-expressing this OsCGA1 to identify the set of genes with altered expression. RNA was extracted from leaves of 4-wk old wild type and OsCGA1 overexpressing rice plants and hybridized to Affymetrix Rice Genome Array. Three biological replicates were sampled for wild type and OX plants.
Project description:Melatonin, a natural phytohormone present in most plants, plays multiple roles in plant growth and stress responses. Although melatonin biosynthesis-related genes have been suggested to possess diverse biological functions, their roles and functional mechanisms in regulating rice grain yield remain largely unexplored. Here, we revealed that a rice caffeic acid O-methyltransferase (OsCOMT) gene is involved in melatonin biosynthesis through in vitro and in vivo evidences. Transgenic assays show OsCOMT significantly delays leaf senescence at the grain filling stage, and then improves photosynthesis efficiency. Further experimental and transcriptomic data suggest that OsCOMT inhibits the degradation of chlorophyll and chloroplast, which in turn delay leaf senescence. Histological analysis also reveals the role of OsCOMT in the development of vascular bundle system in rice. The levels of melatonin and cytokinin were significantly increased in the culm of OsCOMT-overexpression plant relative to those of the wild-type (WT). In the OsCOMT-overexpression line, the cytokinin-biosynthesizing genes were up-regulated and the cytokinin-degrading genes were down-regulated, thereby increasing the cytokinin levels compared with the WT. Thus, OsCOMT-mediated vascular patterning may result from the crosstalk between melatonin and cytokinin. More importantly, OsCOMT significantly increased grain number and yield production of rice in various background, including Nipponbare (NIP) and Suken118 (SK118). Our findings show novel insights into melatonin-mediated leaf senescence and vascular patterning, and provide a new strategy to enhance rice yield production.
2021-11-12 | GSE184400 | GEO
Project description:Cytokinin response genes in rice - meta-analysis
Project description:Rice plants were exogenously sprayed with synthetic phenyl-urea cytokinin under drought stress. Leaf proteome was analyzed for the differential expression of proteins.
Project description:A ChIP-seq analysis revealed 378 targets of OsMADS29, which include genes involved in cytokinin metabolism and auxin signaling, carbohydrate metabolism, transporters and a large number of transcription factors, reflecting on its functional diversity. Chromatin Immunonoprecipitation of MADS29 using antiMADS29 antibody was done using rice 9 DAP seed tissue with total input chromatin and mock immunoprecipitated chromatin as controls
