State Key Laboratory of Vegetable Biobreeding, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing, China.
National Engineering Research Center for Vegetables, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing, China.
Nat Commun. 2024 Jun 28;15(1):5470. doi: 10.1038/s41467-024-49721-z.
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 (BrJMJ18) 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 BrJMJ18 can modulate the expression of BrFLC3, one of the five BrFLC orthologs. Furthermore, ChIP-seq and transcriptome data reveal that BrJMJ18 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.
全球变暖对作物的开花时间和产量有严重影响。组蛋白修饰在植物对环境温度的可塑性方面的作用已有详细记录。然而，调节组蛋白修饰的因素及其在栖息地适应中的作用仍然难以捉摸。在这项研究中，通过全基因组模式分析和数量性状位点（QTL）作图，我们揭示了 BrJMJ18 是调节耐热性的 QTL 的候选基因，该 QTL 调控耐热的甘蓝型油菜亚种 chinensis var. parachinensis（或菜心，简称 Par）的耐热性。BrJMJ18 编码一种 H3K36me2/3 Jumonji 去甲基酶，可重塑整个基因组的 H3K36 甲基化。我们通过对过表达和 CRISPR/Cas9 突变体植物的特征描述，证明了来自 Par 的 BrJMJ18 等位基因（BrJMJ18）通过温度依赖的方式影响开花时间和植物生长。我们进一步表明，BrJMJ18 的过表达可以调节五个 BrFLC 同源物之一 BrFLC3 的表达。此外，ChIP-seq 和转录组数据表明，BrJMJ18 可以在高温下调节叶绿素生物合成。我们还证明，三个氨基酸突变可能导致亚种间 BrJMJ18 功能的差异。基于这些发现，我们提出了一个工作模型，其中 H3K36me2/3 去甲基酶在正常条件下不影响农艺性状，但可以增强甘蓝型油菜在热应激下的弹性。
