Project description:Dongxiang wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.) and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling stage under salt stress compared with those under normal conditions. The analysis results for the sequencing data showed that 6,867 transcripts were differentially expressed in the leaves (2,216 up-regulated and 4,651 down-regulated) and 4,988 transcripts in the roots (3,105 up-regulated and 1,883 down-regulated). Among these differentially expressed genes, the detection of many transcription factor genes demonstrated that multiple regulatory pathways were involved in salt stress tolerance. In addition, the differentially expressed genes were compared with the previous RNA-Seq analysis of salt-stress responses in cultivated rice Nipponbare, indicating the possible specific molecular mechanisms of salt-stress responses for Dongxiang wild rice. A large number of the salt-inducible genes identified in this study were co-localized onto fine-mapped salt-tolerance-related quantitative trait loci, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for salt-stress tolerance in rice.
Project description:Dongxiang wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.) and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling stage under salt stress compared with those under normal conditions. The analysis results for the sequencing data showed that 6,867 transcripts were differentially expressed in the leaves (2,216 up-regulated and 4,651 down-regulated) and 4,988 transcripts in the roots (3,105 up-regulated and 1,883 down-regulated). Among these differentially expressed genes, the detection of many transcription factor genes demonstrated that multiple regulatory pathways were involved in salt stress tolerance. In addition, the differentially expressed genes were compared with the previous RNA-Seq analysis of salt-stress responses in cultivated rice Nipponbare, indicating the possible specific molecular mechanisms of salt-stress responses for Dongxiang wild rice. A large number of the salt-inducible genes identified in this study were co-localized onto fine-mapped salt-tolerance-related quantitative trait loci, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for salt-stress tolerance in rice. Leaf and root mRNA profiles of Dongxiang wild rice at the seedling stage with or without salt stress were generated by deep sequencing, on Illumina Hiseq 2000 platform.
Project description:Rice was domesticated independently in Asia and Africa, leading to two distinct but closely related crop species, Oryza sativa and Oryza glaberrima, respectively. The two domestications lead to morphological changes, in which a higher branching complexity of the panicles, influencing seed production and crop yield. Although much emphasis was placed on changes in transcriptional regulation during rice domestication and improvement, no large-scale study of small RNA regulation changes during domestication has been reported so far. To analyze whether rice domestication has altered the expression of small RNAs, we performed deep sequencing of small RNA transcriptomes from early developmental stages of panicles from 10 genotypes of the cultivated African species and 10 genotypes of its wild-relative O. barthii. Our study shows a drastic expression change of the 21-nucleotide smallRNA population. A total of 29% of these smallRNAs are overexpressed in panicles of O. barthii vs. O. glaberrima, corresponding mainly to 21-nucleotide phased siRNAs (or phasiRNAs). We also show that these changes are associated with a differential expression of a known regulator of phased siRNAs, miR2118 during early panicle development. Finally, these changes are associated to a heterochronic alteration of phasiRNAs and miR2118 expression pattern, during panicle development with a delayed expression in the domesticated species. Our study suggests a major reshaping of the regulation network from a specific class of small RNA during African rice domestication.
Project description:The lack of MIRNA set and genome sequence of O. rufipogon (the ancestor of the cultivated rice) has limited to answer the role of MIRNA genes in rice domestication. In this study, a genome, three small RNA populations and a degradome of O.rufipogon were sequenced by Illumina platform and miRNA expression were investigated by miRNA chips. A de novo genome was assembled using ~55x coverage of raw sequencing data and a total of 387 MIRNAs were identified in the O. rufipogon genome based on ~5.2 million unique small RNA reads from three different tissues of O. rufipogon. Of these O. rufipogon MIRNAs, 259 were not found in the cultivated rice, suggesting loss of these MIRNAs in the cultivated rice. We also found that 48 MIRNAs were novel in the cultivated rice, suggesting that they were potential targets of domestication selection. Some miRNAs showed significant expression difference in the wild and cultivated rice, suggesting that expression of miRNA could also be a target of domestication, as demonstrated for the miR164 family. Our results illustrated MIRNA genes, like protein-coding genes, were significantly shaped during rice domestication and could be one of the driven forces contributed to rice domestication.
Project description:The lack of MIRNA set and genome sequence of O. rufipogon (the ancestor of the cultivated rice) has limited to answer the role of MIRNA genes in rice domestication. In this study, a genome, three small RNA populations and a degradome of O.rufipogon were sequenced by Illumina platform and miRNA expression were investigated by miRNA chips. A de novo genome was assembled using ~55x coverage of raw sequencing data and a total of 387 MIRNAs were identified in the O. rufipogon genome based on ~5.2 million unique small RNA reads from three different tissues of O. rufipogon. Of these O. rufipogon MIRNAs, 259 were not found in the cultivated rice, suggesting loss of these MIRNAs in the cultivated rice. We also found that 48 MIRNAs were novel in the cultivated rice, suggesting that they were potential targets of domestication selection. Some miRNAs showed significant expression difference in the wild and cultivated rice, suggesting that expression of miRNA could also be a target of domestication, as demonstrated for the miR164 family. Our results illustrated MIRNA genes, like protein-coding genes, were significantly shaped during rice domestication and could be one of the driven forces contributed to rice domestication. Non-coding small RNA were generated from three different tissues of O.rufipogon by sequecing using Illumina GAII
Project description:Wild rice species found in tropical and subtropical regions of Asia and Australia; one of the rice species included in the OMAP project.