Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, P. R. China.
National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.
J Exp Bot. 2021 May 28;72(12):4502-4519. doi: 10.1093/jxb/erab120.
Heat stress damages plant tissues and induces multiple adaptive responses. Complex and spatiotemporally specific interactions among transcription factors (TFs), microRNAs (miRNAs), and their targets play crucial roles in regulating stress responses. To explore these interactions and to identify regulatory networks in perennial woody plants subjected to heat stress, we integrated time-course RNA-seq, small RNA-seq, degradome sequencing, weighted gene correlation network analysis, and multi-gene association approaches in poplar. Results from Populus trichocarpa enabled us to construct a three-layer, highly interwoven regulatory network involving 15 TFs, 45 miRNAs, and 77 photosynthetic genes. Candidate gene association studies in a population of P. tomentosa identified 114 significant associations and 696 epistatic SNP-SNP pairs that were linked to 29 photosynthetic and growth traits (P<0.0001, q<0.05). We also identified miR396a and its target, Growth-Regulating Factor 15 (GRF15) as an important regulatory module in the heat-stress response. Transgenic plants of hybrid poplar (P. alba × P. glandulosa) overexpressing a GRF15 mRNA lacking the miR396a target sites exhibited enhanced heat tolerance and photosynthetic efficiency compared to wild-type plants. Together, our observations demonstrate that GRF15 plays a crucial role in responding to heat stress, and they highlight the power of this new, multifaceted approach for identifying regulatory nodes in plants.
热应激会损伤植物组织，并诱导多种适应性反应。转录因子（TFs）、microRNAs（miRNAs）及其靶标之间复杂且具有时空特异性的相互作用，在调节应激反应中起着关键作用。为了探索这些相互作用，并鉴定受热应激影响的多年生木本植物中的调控网络，我们在杨树中整合了时间序列 RNA-seq、小 RNA-seq、降解组测序、加权基因相关网络分析和多基因关联方法。毛果杨的研究结果使我们能够构建一个三层、高度交织的调控网络，涉及 15 个 TF、45 个 miRNA 和 77 个光合作用基因。在一个毛果杨群体中进行的候选基因关联研究，确定了 114 个显著关联和 696 个上位 SNP-SNP 对，它们与 29 个光合作用和生长性状相关（P<0.0001，q<0.05）。我们还鉴定了 miR396a 及其靶标 Growth-Regulating Factor 15（GRF15）作为热应激反应中的一个重要调控模块。过表达缺乏 miR396a 靶位点的 GRF15 mRNA 的杂种杨树（银白杨×腺毛杨）转基因植株与野生型植株相比，表现出增强的耐热性和光合作用效率。总之，我们的观察结果表明，GRF15 在应对热应激中起着至关重要的作用，并强调了这种新的、多方面的方法在鉴定植物调控节点方面的强大功能。
