Project description:Popular rice mega varieties lack sufficient key micronutrients (e.g., Fe, Zn), vitamins and a balanced amino acid composition that are essential for a healthy diet. The major bottleneck for improving the nutritional quality of popular rice varieties through conventional breeding or gene technology is our lack of an integrated understanding of the biochemical and molecular processes that occur during rice grain filling (and their determining genes or loci). In this project, we will perform molecular expression profiling on specific tissue layers of the rice grain. To perform this experiment, the material will be developing rice seeds from plants grown hydroponically under controlled greenhouse conditions. Then, the laser microdissection approach will be applied to dissect different parts of the grain (i.e, vascular trace, aleurone, nucellar epidermis, etc). Total RNA will be extracted from these dissected parts and RNA sequencing will be performed. In this project, we will learn how the synthesis and deposition of grain nutrients is regulated, particularly, during grain filling.
Project description:qTGW3 encodes a GLYCOGEN SYNTHASE KINASE 3 (GSK3)/SHAGGY-like family protein kinase GSK5. We demonstrate that GSK5 interacts with and phosphorylates the AUXIN RESPONSE FACTOR (ARF) transcription factor ARF4. Both GSK5 and ARF4 are mainly expressed in reproductive tissues, and loss-of-function mutation of ARF4 also increases rice grain length and weight. ARF4 functions as a transcriptional repressor in plants and RNA-Seq analysis reveals that, compared to the wild-type plants, totally 887 and 1179 genes were up-regulated in the GSK5 and ARF4 mutants, respectively. Among them, 373 genes were commonly up-regulated in both mutants. In contrast, there were 681 and 669 genes were down-regulated in the GSK5 and ARF4 mutants, respectively. Among them, 288 genes were commonly up-regulated in both mutants. These results showed that GSK5 and ARF4 have overlapping roles and regulate a common set of genes during rice grain development.
Project description:Endogenous small RNAs, including microRNAs (miRNAs) and short-interfering RNAs (siRNAs), function as posttranscriptional or transcriptional regulators in plants. miRNA function is essential for normal development and therefore likely to be important in the growth of the rice grain. To investigate the likely roles of miRNAs in rice grain development we carried out deep sequencing of the small RNA populations of rice grains. A total of 96,091 (including 23,867 reads from vegetative tissues) and 5,379,724 small RNA sequences that are longer than 17nt were generated. Approximately 94% of these small RNAs were 20-24nt in length. The majority of the small RNAs were singletons, indicating that rice genome has a very complex small RNA population, which is harder to be saturated. From these smal RNA sequences we found representatives of all 20 conserved plant miRNA families and evidence for changes in expression of miRNAs during rice grain development. Using an approach based on the presence of the miRNA and miRNA* sequences, we identified 51 novel, non-conserved rice miRNA families expressed in grains with functionally diverse predicted target genes. miRNA-guided cleavage was confirmed for a number of targets genes including ones with roles in sugar signalling and restoration of cytoplasmic male sterility. We identified a likely mirtron, indicating that plants can also use spliced introns as a source of miRNAs. Our sequencing results revealed four TAS3 loci; these all contain dual miR390 sites of which only the 3? site is cleaved. We also found a miRNA-like long hairpin generating phased 21nt small RNAs, strongly expressed in developing grains and show that these small RNAs act in trans to cleave target mRNAs. Keywords: high throughput pyrosequencing, small RNA, microRNA, grain development, rice
Project description:Rice reproductive development is highly sensitive to high temperature stress. In rice flowering occurs over a period of at least 5 days. Heat stress alters the global gene expression dynamics in panicle especially during pollen development, anthesis and grain filling. Some of the rice genotypes like Nagina 22 show better spikelet fertility and grain filling compared to high yielding and popular rice cultivars like IR 64. We carried out microarray analysis of 8 days heat stressed panicles of Nagina22, heat and drought tolerant aus rice cultivar and IR64, a heat susceptible indica genotype along with unstressed samples of Nagina22 and IR64 so as to understand the transcriptome dynamics in these two genotypes under heat stress and to identify the genes important for governing heat stress tolerance in rice.
Project description:High temperature during the grain-filling stage causes deleterious effects on storage material accumulation and grain quality. But it is still unclear how high temperature affects storage materials accumulation. In this study, we systemically analyzed the expression pattern of rice genes under high temperture during the grain-filling stage.
Project description:Developing strategies to increase rice productivity to meet global demand is one of the main challenges for breeders around the world. Here, we report a novel microRNA mediated process that increases rice grain yield in field trials. Expression of target mimicry of microRNA396 (MIM396) significantly increases rice yield by modulating the development of the auxiliary branches and spikelets through promoting the expression of Growth Regulation Factor 6 (OsGRF6). OsGRF6 coordinately induces the expression of several key factors involved in branch and spikelet development, auxin (IAA) biosynthesis, and auxin signaling pathway. Our results demonstrate that the miR396b-GRF6 module acts as a key player in shaping the inflorescence architecture of rice, which could be engineered to generate high-yield rice. This dataset records the profile of the binding peaks of OsGRF6 with GFP antibody in 35S:GRF6-GFP overexpression lines and the differential expressed genes between MIM396 and WT plants. Examination of OsGRF6 regulated genes.
Project description:Enhancing grain production of rice (Oryza sativa L.) is a top priority in ensuring food security for human being. One approach to increase yield is to delay leaf senescence and to extend the available time for photosynthesis. microRNAs (miRNAs) are key regulators for aging and cellular senescence in eukayotes. However, miRNAs and their roles in rice leaf senescence remain unexplored. Here, we report identification of miRNAs and their putative target genes by deep sequencing of six small RNA libraries, six RNA-seq libraries and two degradome libraries from the leaves of two super hybrid rice, Nei-2-You 6 (N2Y6, age-resistant rice) and Liang-You-Pei 9 (LYP9, age-sensitive rice). Totally 372 known miRNAs and 162 miRNA candidates were identified, and 1145 targets were identified. Compared with the expression of miRNAs in the leaves of LYP9, the numbers of miRNAs up-regulated and down-regulated in the leaves of N2Y6 were 47 and 30 at early stage of grain-filling, 21 and 17 at the middle stage, and 11 and 37 at the late stage, respectively. Six miRNA families, osa-miR159, osa-miR160 osa-miR164, osa-miR167, osa-miR172 and osa-miR1848, targeting the genes encoding APETALA2 (AP2), zinc finger proteins, salicylic acid-induced protein 19 (SIP19), Auxin response factors (ARF) and NAC transcription factors, respectively, were found to be involved in leaf senescence through phytohormone signaling pathways. These results provided valuable information for understanding the miRNA-mediated leaf senescence of rice, and offered an important foundation for rice breeding. [miRNA] sample 1:The flag leaves at early stage of grain-filling of N2Y6 rice; sample 2: The flag leaves at middle stage of grain-filling of N2Y6 rice;sample 3:The flag leaves at late stage of grain-filling of N2Y6 rice; sample 4:The flag leaves at early stage of grain-filling of LYP9 rice; sample 5: The flag leaves at middle stage of grain-filling of LYP9 rice;sample 6:The flag leaves at late stage of grain-filling of LYP9 rice. [DGE]: samples 7-12 [degradome (targets)]: samples 13:The flag leaves at mixed stages of grain-filling of N2Y6 rice; sample 14:The flag leaves at mixed stages of grain-filling of LYP9 rice
Project description:To investigate how OsGATA6 regulates heading date, grain number per panicle, and grain phenotypes, we collected panicle primordia of ZH11 and OsGATA6-AM lines at the In2 and In3 stages. We analyzed gene expression using a rice expression profiling chip. Compared with ZH11, OsGATA6-AM lines had 818 up-regulated genes and 284 down-regulated genes
Project description:Gene expression profiling of embryo and endosperm at 7-42 days after flowering (DAT) was performed to obtain an overall signature of the rice transcriptome during grain development and maturation.
Project description:Favorable grain filling ability is crucial for seed development and plant yield1, with less fertilizer applying is the most urgent goals to meet the growing demands of green and safe food. However, the balance mechanism between grain filling and nutrient elements is still unclear so far. Here, we describe a gene GAF1, specially expressed in endosperm aleurone layer, encoding a phosphate transporter, positively controls rice grain filling and seed development and also contributes to phosphate balance was mapped in our study. To study the regulation pattern of GAF1, we performed the RNA-seq analysis of NIL-GAF1 and NIL-gaf1 at middle grain filling stage in seeds. The data shows that many pathways related to starch and sugar metabolism were enriched, and many starch synthesis related genes and phosphate response genes were up-regulated or down-regulated. These data further support that seed specific expressed GAF1 plays a key role in regulating both phosphate homeostasis and seed development. More importantly, overexpression of GAF1 can significantly improve grain filling and thus yield enhanced plant production in field.