Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Zhongguancun, Nandajie No. 12, Haidian District, Beijing, 100081, People's Republic of China.
Planta. 2021 Apr 27;253(5):111. doi: 10.1007/s00425-021-03630-3.
Gene co-expression network analysis of the heat-responsive core transcriptome in two contrasting Brassica rapa accessions reveals the main metabolic pathways, key modules and hub genes, are involved in long-term heat stress. Brassica rapa is a widely cultivated and economically important vegetable in Asia. High temperature is a common stress that severely impacts leaf head formation in B. rapa, resulting in reduced quality and production. The purpose of this study was thus to identify candidate heat tolerance genes by comparative transcriptome analysis of two contrasting B. rapa accessions in response to long-term heat stress. Two B. rapa accessions, '268' and '334', which showed significant differences in heat tolerance, were used for RNA sequencing analysis. We identified a total of 11,055 and 8921 differentially expressed genes (DEGs) in '268' and '334', respectively. Functional enrichment analyses of all of the identified DEGs, together with the genes identified from weighted gene co-expression network analyses (WGCNA), revealed that the autophagy pathway, glutathione metabolism, and ribosome biogenesis in eukaryotes were significantly up-regulated, whereas photosynthesis was down-regulated, in the heat resistance of B. rapa '268'. Furthermore, when B. rapa '334' was subjected to long-term high-temperature stress, heat stress caused significant changes in the expression of certain functional genes linked to protein processing in the endoplasmic reticulum and plant hormone signal transduction pathways. Autophagy-related genes might have been induced by persistent heat stress and remained high during recovery. Several hub genes like HSP17.6, HSP17.6B, HSP70-8, CLPB1, PAP1, PYR1, ADC2, and GSTF11 were discussed in this study, which may be potential candidates for further analyses of the response to long-term heat stress. These results should help elucidate the molecular mechanisms of heat stress adaptation in B. rapa.
两个甘蓝型油菜品种在热响应核心转录组的基因共表达网络分析中揭示了主要代谢途径、关键模块和枢纽基因，这些基因参与了长期热胁迫。甘蓝型油菜是亚洲广泛种植和经济上重要的蔬菜。高温是一种常见的胁迫，严重影响甘蓝型油菜的叶球形成，导致品质和产量下降。因此，本研究旨在通过比较两个甘蓝型油菜品种对长期热胁迫的转录组分析，鉴定候选耐热基因。利用 RNA 测序分析，我们选择了两个具有显著耐热差异的甘蓝型油菜品种 '268' 和 '334'。我们分别在 '268' 和 '334' 中鉴定到了总共 11055 个和 8921 个差异表达基因（DEGs）。对所有鉴定的 DEGs 以及来自加权基因共表达网络分析（WGCNA）的基因进行功能富集分析表明，自噬途径、谷胱甘肽代谢和真核生物核糖体生物发生在甘蓝型油菜 '268' 的耐热性中显著上调，而光合作用则下调。此外，当甘蓝型油菜 '334' 受到长期高温胁迫时，高温胁迫导致与内质网中蛋白质加工和植物激素信号转导途径相关的某些功能基因的表达发生显著变化。持续的热胁迫可能诱导了自噬相关基因的表达，并在恢复过程中保持高水平。本研究讨论了几个枢纽基因，如 HSP17.6、HSP17.6B、HSP70-8、CLPB1、PAP1、PYR1、ADC2 和 GSTF11，它们可能是进一步分析对长期热应激响应的潜在候选基因。这些结果有助于阐明甘蓝型油菜适应热应激的分子机制。
