Salt-responsive genes are differentially regulated at the chromatin level between the leaf and root tissues in rice [RNA-Seq]
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ABSTRACT: To elucidate the epigenetic regulation of salt-responsive genes helps to understand the underlying mechanisms that confer salt tolerance in rice. However, it is still largely unknown how epigenetic mechanisms function in regulating the salt-responsive genes in rice and other crops at a global level. In this study, we mainly focused on dynamic changes in transcriptome and histone marks between rice leaf and root tissues during salt treatment by using RNA-seq and ChIP-seq approaches. We demonstrated that the majority of salt-related differentially expressed genes (DEGs) display tissue-dependent changes. Similarly, tissue-dependent chromatin changes have been detected between leaf and root tissues during salt treatment. Most importantly, our study indicates that chromatin states with a combination of marks, rather than an individual mark, most likely play crucial roles in regulating differential expression of salt-responsive genes between leaf and root tissues. Especially, a special CS containing bivalent marks, H3K4me3 and H3K27me3 with a functional exclusion with each other, displays distinct functions in regulating expression of DEGs between leaf and root tissues, H3K27me3-related repressive mark mainly regulates expression of DEGs in root, but H3K4me3-releated active mark dominantly functions in regulation of down-regulated genes and possibly antagonize the repressive role of H3K27me3 in up-regulated genes in leaf. Thus, our findings indicate salt-responsive genes are differentially regulated at the chromatin level between the leaf and root tissues in rice, which provides new insights in the understanding of chromatin-based epigenetic mechanisms that confer salt tolerance in plants.
Project description:To elucidate the epigenetic regulation of salt-responsive genes helps to understand the underlying mechanisms that confer salt tolerance in rice. However, it is still largely unknown how epigenetic mechanisms function in regulating the salt-responsive genes in rice and other crops at a global level. In this study, we mainly focused on dynamic changes in transcriptome and histone marks between rice leaf and root tissues during salt treatment by using RNA-seq and ChIP-seq approaches. We demonstrated that the majority of salt-related differentially expressed genes (DEGs) display tissue-dependent changes. Similarly, tissue-dependent chromatin changes have been detected between leaf and root tissues during salt treatment. Most importantly, our study indicates that chromatin states with a combination of marks, rather than an individual mark, most likely play crucial roles in regulating differential expression of salt-responsive genes between leaf and root tissues. Especially, a special CS containing bivalent marks, H3K4me3 and H3K27me3 with a functional exclusion with each other, displays distinct functions in regulating expression of DEGs between leaf and root tissues, H3K27me3-related repressive mark mainly regulates expression of DEGs in root, but H3K4me3-releated active mark dominantly functions in regulation of down-regulated genes and possibly antagonize the repressive role of H3K27me3 in up-regulated genes in leaf. Thus, our findings indicate salt-responsive genes are differentially regulated at the chromatin level between the leaf and root tissues in rice, which provides new insights in the understanding of chromatin-based epigenetic mechanisms that confer salt tolerance in plants.
Project description:Abiotic stresses such as salinity are very important factors limiting rice growth and productivity around the world. Affymetrix rice genome array containing 48,564 japonica and 1,260 indica sequences was used to analyze the gene expression pattern of rice responsive to salinity stress, try to elucidate the difference of genome-wide gene expression profiling of two contrasting rice genotypes in response to salt stress and to discover the salinity related genes and gene interaction and networks. Under salinity condition, the number of differentially expressed genes (DEGs) in 177-103 was more than that in IR64, and most of up-regulated DEGs in 177-103 are response to stress. But in IR64, most of up-regulated DEGs are transcription related genes. The DEGs under salinity showed very strong tissue specificity, the number of DEGs in leaf was more than that in root. A lot of genes differentially expressed by exogenous ABA treatment under salinity condition, such as Leaf senescence protein, 1-deoxy-D-xylulose 5-phosphate synthase 2 precursor and Protein of unknown function DUF26 were induced by ABA and contributed to salinity tolerance. In this study, the gene expression patterns across two organs including leaves and roots at seedling stage were characterized under control, salinity, salinity+ABA treatments by using the Affymetrix rice microarray platform based on a salinity tolerant rice line derived from IR64.
Project description:Abiotic stresses such as salinity are very important factors limiting rice growth and productivity around the world. Affymetrix rice genome array containing 48,564 japonica and 1,260 indica sequences was used to analyze the gene expression pattern of rice responsive to salinity stress, try to elucidate the difference of genome-wide gene expression profiling of two contrasting rice genotypes in response to salt stress and to discover the salinity related genes and gene interaction and networks. Under salinity condition, the number of differentially expressed genes (DEGs) in 177-103 was more than that in IR64, and most of up-regulated DEGs in 177-103 are response to stress. But in IR64, most of up-regulated DEGs are transcription related genes. The DEGs under salinity showed very strong tissue specificity, the number of DEGs in leaf was more than that in root. A lot of genes differentially expressed by exogenous ABA treatment under salinity condition, such as Leaf senescence protein, 1-deoxy-D-xylulose 5-phosphate synthase 2 precursor and Protein of unknown function DUF26 were induced by ABA and contributed to salinity tolerance.
Project description:We report the application of small RNA sequencing (Illumina) technology for the identification of miRNA from root and leaf tissues of pokkali rice cultivar grown under normal and salt stress conditions. We used this data to predict and identify known and novel miRNAs.
Project description:We report the application of small RNA sequencing (Illumina) technology for the identification of miRNA from root and leaf and flower tissues of pusa basmati rice cultivar grown under normal and salt stress conditions. We used this data to predict and identify known and novel miRNAs.
Project description:The aim of this study was to characterize the tissue tolerance mechanisms of rice under salt stress. Our preliminary experiment identified a japonica rice landrace Shuzenji-kokumai (SZK), which is considered to be tissue-tolerant because it can maintain better growth than salt-sensitive rice while having a high Na+ concentration in the shoots under salt stress. These mechanisms differ from those of most salt-tolerant rice varieties, which have low Na+ concentrations in the shoots. We compared the physiological and molecular characteristics of SZK with those of FL478, a salt-tolerant variety, and Kunishi, a salt-sensitive variety. Under salt stress conditions, SZK accumulated high levels of Na+ in roots, leaf sheaths, and leaf blades, which were almost as high as those in the salt-sensitive Kunishi. Simultaneously, SZK maintained better growth and physiological status, as determined by its higher dry weight, lower electrolyte leakage ratio, and lower malondialdehyde concentration. OsNHX1 and OsNHX2 were up-regulated in the leaf sheaths of SZK, suggesting that Na+ is compartmentalized in the vacuole to avoid Na+ toxicity. In contrast, FL478 showed up-regulation of OsHKT1;5 and OsSOS1 in the roots, which exclude Na+ from the shoots. RNA-seq analysis showed that 4623 and 1998 differentially expressed genes (DEGs) were detected in the leaf sheaths and leaf blades of SZK, respectively. Among them, the HSP (heat shock protein) gene expression was highly up-regulated only in SZK, indicating that SZK protects against the protein damage caused by Na+ toxicity. Our findings suggest that SZK has atypical survival mechanisms under salt-stress conditions. These mechanisms offer potential traits for improving salt tolerance in rice.
Project description:Comparative transcriptome sequencing in leaf and root tissues of Control and Salt-treated Oryza sativa generated 52.2 and 17.29 million high-quality reads.
Project description:We report the application of 6mA IP-sequencing technology for high-throughput profiling in rice tissues of 12 days' leaf. By obtaining over 20 million high quality clean mapping sequenced reads from immunoprecipitated DNA, we generate genome-wide 6mA maps of rice 12 days' leaf. Using mass spectrometry and immunoprecipitation and validation with analysis of single-molecule real-time sequencing, we observed that about 0.2% of all adenines are 6mA-methylated in the rice genome. 6mA occurs most frequently at GAGG motifs and is mapped to about 20% of genes and 14% of transposable elements (TEs). In promoters, 6mA marks silent genes, but in bodies correlates with gene activity. 6mA overlaps with 5-methylated cytosine (5mC) at CG sites in gene bodies and is complementary to 5mC at CHH sites in TEs. We show that OsALKBH1 may be potentially involved in 6mA demethylation in rice. The results suggest that 6mA is complementary to 5mC as an epigenomic mark in rice and reinforces a distinct role for 6mA as a gene-expression associated epigenomic mark in eukaryotes.
Project description:The JA deficient mutant (aoc) showed weaker symptoms than WT when both are exposed to salt. JAs signaling in WT, appeared then to impair salt tolerance and we were interested, through this transcriptomic approach, to highlight the JA-dependent component of the salt stress response that could explain the differential phenotype We report, for root and 2nd leaf, the compared transcriptomes of WT and aoc, before and at 3 different times (1 h, 6 h and 72 h) after salt exposure. The study reveals some key JA-regulated negative and positive effectors of salt stress tolerance in rice
Project description:A tandem mass tag (TMT)-based comparative peptidomics analysis of rice seedlings under salt stress was conducted. Rice seedlings were exposed to 50 and 150 mM NaCl for 24 and 72 h, respectively, and the root and shoot tissues of different treatment groups were collected separately for the peptidomic analysis.