Project description:Using the HiSeqTM 2000 sequencing platform, the anther transcriptome of photo thermo sensitive genic male sterile lines (PTGMS) rice Y58S and P64S (Peiâai 64S) were analyzed at the fertility sensitive stage under cold stress.These datas would be most beneficial for further studies investigating the molecular mechanisms of rice responses to cold stress.
Project description:Leaf rolling and discoloration are two chilling injury symptoms that are widely adopted as indicators for evaluation of cold tolerance at the seedling stage in rice, respectively. However, their relationship has not been well investigated, in particular the mechanism on how low temperature causes leaf rolling at a genome-wide level. In this study, a cold-tolerant japonica cultivar Lijiangxintuanheigu and a cold-sensitive indica cultivar Sanhuangzhan-2 were subjected to different low temperature treatments and physiological and genome-wide gene expression analysis were conducted. Our results showed that leaf rolling happened at temperatures lower than 11℃, but discoloration appeared at moderately low temperatures, such as 13℃. Chlorophyll contents of the two cultivars significantly decreased under 13℃, but didn’t change under 11℃. Contrastly, their relative water contents and the relative electrolyte leakages decreased significantly. Genome-wide gene expression profiling of LTH revealed that the calcium signaling related genes and the genes related to ABA degradation significantly changed under 11℃. Moreover, numerous genes in DREB, MYB, bZIP, NAC, Zin finger, bHLH, WRKY gene families were differently expressed. Furthermore, many aquaporin genes, the key genes in trehalose and starch synthesis were down-regulated under 11℃. These results suggest that the two chilling injury symptoms are controlled by different mechanisms. Cold-induced leaf rolling is associated with calcium and ABA signaling pathways, and subjected to regulation of multiple transcription regulators. The suppression of aquaporin genes and reduced accumulation of soluble sugars under cold stress result in reduction of water potential in cells and consequently, leaf rolling.
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: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:Chilling stress is a major abiotic stress that affects rice growth and development. Rice seedlings are quite sensitive to chilling stress and this harms global rice production. Comprehensive studies of the molecular mechanisms for response to low temperature are of fundamental importance to chilling tolerance improvement. The number of identified cold regulated genes (CORs) in rice is still very small. Circadian clock is an endogenous timer that enables plants to cope with forever changing surroundings including light–dark cycles imposed by the rotation of the planet. Previous studies have demonstrated that the circadian clock regulates stress tolerances in plants show circadian clock regulation of plant stress tolerances. However, little is known about coordination of the circadian clock in rice chilling tolerance. In this study, we investigated rice responses to chilling stress under conditions with natural light-dark cycles. We demonstrated that chilling stress occurring at nighttime significantly decreased chlorophyll content and photosynthesis efficiency in comparison with that occurring at daytime. Transcriptome analysis characterized novel CORs in indica rice, and suggested that circadian clock obviously interferes with cold effects on key genes in chlorophyll (Chl) biosynthesis pathway and photosynthesis-antenna proteins. Expression profiling revealed that chilling stress during different Zeitberger times (ZTs) at nighttime repressed the expression of those genes involved Chl biosynthesis and photosynthesis, whereas stress during ZTs at daytime increases their expression dramatically. Moreover, marker genes OsDREBs for chilling tolerance were regulated differentially by the chilling stress occurring at different ZTs. The phase and amplitude of oscillation curves of core clock component genes such as OsLHY and OsPRR1 are regulated by chilling stress, suggesting the role of chilling stress as an input signal to the rice circadian clock. Our work revealed impacts of circadian clock on chilling responses in rice, and proved that the effects on the fitness costs are varying with the time in a day when the chilling stress occurs.
Project description:Long non-coding RNAs (lncRNAs) are essential regulators of a broad range of biological processes in plants. Spectacular progress in next-generation sequencing technologies has enabled genome-wide identification of lncRNAs in multiple plant species. In this study, genome-wide lncRNA sequencing technology was used to identify cold-responsive lncRNAs at the booting stage in rice by comparison of a tolerant variety, Kongyu131 (KY131), and a sensitive variety, Dongnong422 (DN422). GO and KEGG enrichment analysis were performed, focusing on the cis- and trans- target genes of differential lncRNAs. To identify cold-responsive genes, a meta-analysis was used to integrate cold-tolerant QTLs at the booting stage. In total, 13 cold-responsive target genes were obtained by KEGG enrichment analysis combined with meta-analysis, as confirmed by qRT-PCR. Finally, three of these genes were identified in response to cold stress. These results sought to provide new insight into cold-resistance research for rice.