Soil salinity is a major source of abiotic plant stress, adversely affecting plant growth, development and productivity. Although the physiological and molecular mechanisms that underlie plant responses to salt stress are becoming increasingly understood, epigenetic modifications, such as histone methylations and their potential regulation of the transcription of masked genes at the genome level in response to salt stress, remain largely unclear. Castor bean, an important nonedible oil crop, has evolved the capacity to grow under salt stress. Here, based on high-throughput RNA-seq and ChIP-seq data, we systematically investigated changes in genomic transcription and histone methylation using typical histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 tri-methylated lysine 27 (H3K27me3) markers in castor bean leaves subjected to salt stress. The results showed that gain or loss of histone methylation was closely associated with activated or repressed gene expression, though variations in both transcriptome and histone methylation modifications were relatively narrow in response to salt stress. Diverse salt responsive genes and switched histone methylation sites were identified in this study. In particular, we found for the first time that the transcription of the key salt-response regulator RADIALIS-LIKE SANT (RSM1), a MYB-related transcription factor involved in ABA(abscisic acid)-mediated salt stress signaling, was potentially regulated by bivalent H3K4me3-H3K27me3 modifications. Combining phenotypic variations with transcriptional and epigenetic changes, we provide a comprehensive profile for understanding histone modification, genomic transcription and their associations in response to salt stress in plants.

中文翻译：

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蓖麻的基因组转录和组蛋白甲基化与盐胁迫的变化及其相关性。

土壤盐分是非生物植物胁迫的主要来源，对植物的生长，发育和生产力产生不利影响。尽管植物对盐胁迫的响应的生理和分子机制已变得越来越了解，但表观遗传修饰（例如组蛋白甲基化及其对盐胁迫响应的基因组水平上被掩盖基因转录的潜在调控）仍不清楚。蓖麻子是重要的非食用油作物，已经进化出在盐胁迫下的生长能力。在这里，基于高通量RNA-seq和ChIP-seq数据，我们使用蓖麻中典型的组蛋白H3赖氨酸4三甲基化（H3K4me3）和组蛋白H3三甲基化赖氨酸27（H3K27me3）标记，系统地研究了基因组转录和组蛋白甲基化的变化。豆叶遭受盐胁迫。结果表明，组蛋白甲基化的得失与丢失与激活或受抑制的基因表达密切相关，尽管转录组和组蛋白甲基化修饰的变化相对于盐胁迫而言相对较窄。在这项研究中鉴定出不同的盐反应基因和组蛋白甲基化位点。特别是，我们首次发现关键的盐反应调节因子RADIALIS-LIKE SANT（RSM1）的转录可能受ABA（脱落酸）介导的盐胁迫信号传导的调控，该转录因子参与MYB相关转录因子。二价H3K4me3-H3K27me3修饰。将表型变异与转录和表观遗传变化相结合，我们为了解组蛋白修饰提供了全面的资料，