Project description:Cellularization is a key event during the development of the endosperm. Our understanding of the developmental regulation of cellularization has been limited for plants other than Arabidopsis. We found that the activation of OsbZIP76 coincided with the initiation of cellularization of rice. Either knockdown or knockout of OsbZIP76 led to precocious cellularization. Many genes involved in endosperm development or starch biosynthesis were prematurely activated in the caryopsis at two days after fertilization. The results implied that OsbZIP76 is involved in the regulation of cellularization in rice. As a putative transcription factor, OsbZIP76 alone lacked transcriptional activation activity. However, it was able to interact with OsNF-YB9 and OsNF-YB1, two nuclear factor Y (NF-Y) family transcription factors, both in yeast and in planta. OsbZIP76 and OsNF-YB9 showed similar endosperm-preferential expression patterns and the transiently expressed proteins were colocalized in the epidermal cells of tobacco. As with osnf-yb1 mutants, the osbzip76 mutants showed reduced seed size and reduced apparent amylose content of the seeds. We also confirmed that OsbZIP76 is an imprinted gene in rice, the expression of which depended on the genetic background. Our results suggested that OsbZIP76 is an endosperm-expressed imprinted gene to regulate development of the endosperm in rice.
Project description:Higher temperature conditions during the final stages of rice seed development (seed filling and maturation) are known to cause damage to both rice yield and rice kernel quality. Japan, especially western and central parts, has seen record high temperatures in the last decade, and the rice kernel quality has decreased; specifically a reduction the first-grade of rice has been seen. In this study, we specifically looked at the harvested rice in a town of the central Kanto-plains (Japan) during the year 2010, which saw day-time temperatures go above the critical limits ranging from 34 to 38C at the final stages of seed development and maturity to investigate high-temperature effects in the actual field condition. Three sets of dry mature rice seeds (commercial) were obtained Japan Agriculture (JA Zen-Noh) branch in Ami-town of Ibaraki prefecture in September 2010, as grade 1 (labeled as Y1), grade 2 (labeled as Y2), and grade 3 (out-of-grade, labeled as Y3). The research objective was to examine in particular alterations in gene expressions genome-wide in grade 2 (Y2) and grade 3 (Y3) seeds over the grade 1 (Y1) following the high-temperature spike using a high-throughput omic-approach DNA microarray (Agilent 4 x 44K rice oligo DNA chip) in conjunction with MapMan bioinformatics analysis. Rice seed quality analysis revealed, as expected, low quality in Y3 > Y2 over Y1, in taste, amylose, protein and fatty acid degree, but not in water content. Transcriptome profiling data revealed 124 and 373 up-regulated and 106 and 129 down-regulated genes in Y2 and Y3, respectively. Bioinformatics analysis of differentially expressed genes revealed changes in function of genes related to metabolism, including starch metabolism (e.g., alpha amylase), defense/stress response, fatty acid biosynthesis and hormones. This research provides for the first time the seed transcriptome profile for the classified low grades (2 and out-of-grade) of rice under an actual stressed environmental condition of high temperature.
Project description:Rice is one of the most important global food crops, and is also a model organism for cereal research 31 . Complete genome sequencing of rice, together with advances in transcriptomics and proteomics, has had a dramatic impact on plant growth and 5 breeding programs 32 . Genomic analysis of DNA methylation in rice has revealed methylation patterns associated with gene bodies and promoters, and the occurrence of high levels of DNA methylation in the centromeric domain 33 . A genome-wide investigation of acetylation in rice revealed that H3K9ac and H3K27ac are mainly enriched at transcription start sites associated with active transcription 34 . Furthermore, global proteome analysis has shown that phosphorylation and succinylation are involved in diverse cellular and metabolic processes 35, 36 . However, despite these considerable advances in our knowledge, additional large-scale analysis of the lysine acetylome in rice is expected to identify many more Kac sites and acetylated proteins in this improtant crop plant. In this study, affinity enrichment and high-resolution LC-MS/MS were used for large-scale analysis of the lysine acetylome in rice variety Nipponbare. In total, 1353 lysine acetylation sites were detected in 866 protein groups in rice seedlings. Proteomic analysis showed that Kac occurs in proteins involved in diverse biological processes with varied cellular functions and subcellular localization.
Project description:In order to identify new miRNAs, NAT-siRNAs and possibly abiotic-stress regulated small RNAs in rice, three small RNA libraries were constructed from control rice seedlings and seedlings exposed to drought or salt stress, and then subjected to pyrosequencing.
Project description:We analyzed the transcriptome profiles for rice grain from heat-tolerant and -sensitive lines in response to high night temperatures at the early milky stage using the Illumina Sequencing method. On the 8th day after the labeled florets flowered, plants with the same label were transferred to chambers and maintained at a temperature of 38.0â±â0.5°C (treatment) or 25.0â±â0.5°C (control) for the dark period (10 h), and 26.0â±â0.5°C (both treatment and control) for the light period (14 h). Three biological replicates of the temperature treatments were grown under the same conditions. After 48 h of treatment, samples containing 45 grains with labels from the same region (middle to bottom part) of labelled ears were harvested, packed in aluminum foil, and flash-frozen in liquid nitrogen until further use. A total of 12 rice grain samples were harvested, i.e., controls (TC1, TC2 and TC3) and treatments (TT1, TT2 and TT3) of the three biological replicates of the heat-tolerant line, and controls (SC1, SC2 and SC3) and treatments (ST1, ST2 and ST3) of the three biological replicates of the heat-sensitive line.
Project description:Lysine acetylation is a dynamic and reversible post-translational modification that plays an imporant role in the gene transcription regulation. Here, we report high quality proteome-scale data for lysine-acetylation sites and proteins in rice (Oryza sativa). A total of 1337 Kac sites in 716 Kac proteins with diverse biological functions and subcellular localizations were identified in rice seedlings.
Project description:Here, we present OryzaPG-DB, a rice proteome database based on shotgun proteogenomics, which incorporates the genomic features of experimental shotgun proteomics data. This version of the database was created from the results of 27 nanoLC-MS/MS runs on a hybrid ion trap-orbitrap mass spectrometer, which offers high accuracy for analyzing tryptic digests from undifferentiated cultured rice cells. Peptides were identified by searching the product ion spectra against the protein, cDNA, transcript and genome databases from Michigan State University, and were mapped to the rice genome. Approximately 3200 genes were covered by these peptides and 40 of them contained novel genomic features. Users can search, download or navigate the database per chromosome, gene, protein, cDNA or transcript and download the updated annotations in standard GFF3 format, with visualization in PNG format. In addition, the database scheme of OryzaPG was designed to be generic and can be reused to host similar proteogenomic information for other species. OryzaPG is the first proteogenomics-based database of the rice proteome, providing peptide-based expression profiles, together with the corresponding genomic origin, including the annotation of novelty for each peptide.