Lab of Landscape Plant Genetics and Breeding, School of Life Science, Nantong University, Nantong, China.
College of Horticulture, Nanjing Agricultural University, Nanjing, China.
PLoS One. 2020 Aug 6;15(8):e0236129. doi: 10.1371/journal.pone.0236129. eCollection 2020.
Salix matsudana, a member of Salicaceae, is an important ornamental tree in China. Because of its capability to tolerate high salt conditions, S. matsudana also plays an important ecological role when grown along Chinese coastal beaches, where the salinity content is high. Here, we aimed to elucidate the mechanism of higher salt tolerance in S. matsudana variety '9901' by identifying the associated genes through RNA sequencing and comparing differential gene expression between the S. matsudana salt-tolerant and salt-sensitive samples treated with 150 mM NaCl. Transcriptomic comparison of the roots of the two samples revealed 2174 and 3159 genes responsive to salt stress in salt-sensitive and salt-tolerant sample, respectively. Real-time polymerase chain reaction analysis of 9 of the responsive genes revealed a strong, positive correlation with RNA sequencing data. The genes were enriched in several pathways, including carbon metabolism pathway, plant-pathogen interaction pathway, and plant hormone signal transduction pathway. Differentially expressed genes (DEGs) encoding transcription factors associated with abiotic stress responses and salt stress response network were identified; their expression levels differed between the two samples in response to salt stress. Hub genes were also revealed by weighted gene co-expression network (WGCNA) analysis. For functional analysis of the DEG encoding sedoheptulose-1,7-bisphosphatase (SBPase), the gene was overexpressed in transgenic Arabidopsis, resulting in increased photosynthetic rates, sucrose and starch accumulation, and enhanced salt tolerance. Further functional characterization of other hub DEGs will reveal the molecular mechanism of salt tolerance in S. matsudana and allow the application of S. matsudana in coastal afforestation.
旱柳是杨柳科的一员，是中国重要的观赏树种。由于其耐高盐的能力，旱柳在中国沿海滩涂地区生长时也具有重要的生态作用，这些地区的盐度很高。在这里，我们通过 RNA 测序鉴定相关基因，并比较经 150mM NaCl 处理的旱柳耐盐和盐敏感样本之间的差异基因表达，旨在阐明旱柳品种'9901'的更高耐盐机制。对两个样本的根进行转录组比较，发现盐敏感和耐盐样本分别有 2174 个和 3159 个基因对盐胁迫有响应。对 9 个响应基因的实时聚合酶链反应分析显示，与 RNA 测序数据具有很强的正相关性。这些基因富集在几个途径中，包括碳代谢途径、植物-病原体相互作用途径和植物激素信号转导途径。鉴定出与非生物胁迫反应和盐胁迫反应网络相关的差异表达基因（DEG）编码转录因子；它们在两个样本中对盐胁迫的表达水平不同。加权基因共表达网络分析（WGCNA）还揭示了枢纽基因。为了对编码 sedoheptulose-1,7-bisphosphatase（SBPase）的 DEG 进行功能分析，该基因在转基因拟南芥中过表达，导致光合速率、蔗糖和淀粉积累增加，耐盐性增强。对其他枢纽 DEG 的进一步功能表征将揭示旱柳耐盐的分子机制，并允许将旱柳应用于沿海造林。
