PDF(Pubmed)
Abstract：
Global warming has a severe impact on the flowering time and yield of crops. Histone modifications have been well-documented for their roles in enabling plant plasticity in ambient temperature. However, the factor modulating histone modifications and their involvement in habitat adaptation have remained elusive. In this study, through genome-wide pattern analysis and quantitative-trait-locus (QTL) mapping, we reveal that BrJMJ18 is a candidate gene for a QTL regulating thermotolerance in thermotolerant B. rapa subsp. chinensis var. parachinensis (or Caixin, abbreviated to Par). BrJMJ18 encodes an H3K36me2/3 Jumonji demethylase that remodels H3K36 methylation across the genome. We demonstrate that the BrJMJ18 allele from Par (BrJMJ18Par) influences flowering time and plant growth in a temperature-dependent manner via characterizing overexpression and CRISPR/Cas9 mutant plants. We further show that overexpression of BrJMJ18Par can modulate the expression of BrFLC3, one of the five BrFLC orthologs. Furthermore, ChIP-seq and transcriptome data reveal that BrJMJ18Par can regulate chlorophyll biosynthesis under high temperatures. We also demonstrate that three amino acid mutations may account for function differences in BrJMJ18 between subspecies. Based on these findings, we propose a working model in which an H3K36me2/3 demethylase, while not affecting agronomic traits under normal conditions, can enhance resilience under heat stress in Brassica rapa.
摘要：
全球变暖对作物的开花时间和产量有严重影响。组蛋白修饰在环境温度下使植物可塑性中的作用已得到充分证明。然而,调节组蛋白修饰的因素及其在栖息地适应中的参与仍然难以捉摸。在这项研究中,通过全基因组模式分析和数量性状基因座（QTL）作图，我们发现BrJMJ18是在耐热B.rapa亚种中调节耐热性的QTL的候选基因。中国.Parachinensis(或财新，缩写为Par）。BrJMJ18编码H3K36me2/3Jumonji去甲基酶，可在整个基因组中重塑H3K36甲基化。我们证明了来自Par（BrJMJ18Par）的BrJMJ18等位基因通过表征过表达和CRISPR/Cas9突变植物以温度依赖性方式影响开花时间和植物生长。我们进一步表明，BrJMJ18Par的过表达可以调节五个BrFLC直系同源物之一BrFLC3的表达。此外，ChIP-seq和转录组数据表明，BrJMJ18Par可以在高温下调节叶绿素的生物合成。我们还证明了三个氨基酸突变可能是BrJMJ18亚种之间功能差异的原因。基于这些发现,我们提出了一个工作模型，其中H3K36me2/3去甲基酶，虽然在正常条件下不影响农艺性状，可以增强芸苔属植物在热胁迫下的恢复力。
