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:The small RNAs presented here were produced as a preliminary exploration of small RNAs in rice, and as such, various tissues and stress conditions were sampled. Small RNAs present in these samples were all mapped to the rice genome TIGR version 5. The total number of distinct mapped sequences are 12879 for Run 1 and 88508 for Run 2. The total number of sequence reads were respectively 70406 and 191682. The datasets contain Oryza sativa var Nipponbar endogenous small RNA sequences in the size range 18 to 34 nt. Plants were grown in a Conviron Environmental Chamber at high light intensity using both high pressure sodium and metal halide lamps for 10.5 hr at 28 degrees C and for 13.5 hr at 26 degrees C in the dark. RNA was extracted from rice tissues at various stages of development and under different abiotic and biotic stresses. The small RNAs presented here were all mapped to the rice genome TIGR version 5. The total number of distinct mapped sequences are 12879 for Run 1 and 88508 for Run 2. The total number of sequence reads were respectively 70406 and 191682.
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. Totally three sets of small RNAs, which were obtained under normal condition as well as salt and drought stress conditions
Project description:Changes in patterns of gene expression are believed to be responsible for the phenotypic differences within and between species. Although the evolutionary significance of functional mutations has been emphasized in rice domestication, little is known about the differences in gene regulation underlying the phenotypic diversification among rice varieties. MicroRNAs (miRNAs) are small regulatory RNAs that play crucial roles in regulating post-transcriptional gene expression. Here, we studied the variation in the expression of both miRNAs and mRNA transcripts in three indica and three japonica rice varieties using RNA sequencing (RNA-seq) to examine the miRNA regulatory effect on target gene expression in rice. In total, 71.0%, 9.2%, and 1.5% of the expressed mature miRNAs showed tissue, subspecies, and tissue-subspecies interaction-biased expression. Most of these differentially expressed miRNAs are evolutionarily weakly conserved. To examine the miRNA regulatory effect on global gene expression under endogenous conditions, we performed pair-wise correlation coefficient analyses on the expression levels of 240 mature miRNAs and 1178 messenger RNAs (mRNAs) both globally and for each specific miRNA-mRNA pair. We found that the deeply conserved miRNAs can significantly decrease the target mRNA abundance. In addition, a total of 109 miRNA-mRNA pairs were identified as significantly correlated pairs (Adjusted p<0.01). Of those, 41 pairs showed positive correlations, while 68 pairs showed negative correlations. Functional analysis elucidated that these mRNAs belonged to different biological pathways that could regulate the stress response, metabolic processes, and rice development. In conclusion, the joint interrogation of miRNA and mRNA expression profiles in this study proved useful for the study of the role of miRNA expression and regulation in the plant transcriptome.
Project description:LongSAGE library in this series are from 'Whole Genome Analysis of Pathogen-Host Recognition and Subsequent Responses in the Rice Blast Patho-System' project. This work is supported by NSF-PGRP #0115642. Keywords: other
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:Cultivated rice (Oryza sativa L.) is frequently exposed to multiple stresses, including Schizotetranychus oryzae mite infestation. Rice domestication has narrowed the genetic diversity of the species, leading to a wide susceptibility. This work aimed to observe the response of two wild rice species (Oryza barthii and O. glaberrima) and two O. sativa genotypes (cv. Nipponbare and f. spontanea) to S. oryzae infestation. Surprisingly, leaf damage, histochemistry, chlorophyll concentration and fluorescence showed that the wild species present higher level of leaf damage, increased accumulation of H2O2 and lower photosynthetic capacity when compared to O. sativa genotypes under infested conditions. Infestation decreased tiller number, except in Nipponbare. Infestation also caused the death of wild plants during the reproductive stage. While infestation did not affect the weight of 1,000 grains in both O. sativa genotypes, the number of panicles per plant was affected only in f. spontanea, and the percentage of full seeds per panicle and seed length were increased only in Nipponbare. Using proteomic analysis, we identified 195 differentially abundant proteins when comparing susceptible (O. barthii) and tolerant (Nipponbare) genotypes under control and infested conditions. O. barthii has a less abundant antioxidant arsenal and is unable to modulate proteins involved with general metabolism and energy production under infested condition. Nipponbare presents high abundance of detoxification-related proteins, general metabolic processes and energy production, suggesting that, under infested condition, the primary metabolism is maintained more active compared to O. barthii. Also, under infested conditions, Nipponbare presents higher levels of proline and a greater abundance of defense-related proteins, such as osmotin, ricin B-like lectin, and protease inhibitors. These differentially abundant proteins can be used as biotechnological tools in breeding programs aiming increased tolerance to mite infestation.