College of Agronomy, Henan Agricultural University, Zhengzhou, China.
Ann Bot. 2022 Nov 17;130(5):717-735. doi: 10.1093/aob/mcac102.
The North China Plain, the highest winter-wheat-producing region of China, is seriously threatened by drought. Traditional irrigation wastes a significant amount of water during the sowing season. Therefore, it is necessary to study the drought resistance of wheat during germination to maintain agricultural ecological security. From several main cultivars in the North China Plain, we screened the drought-resistant cultivar JM47 and drought-sensitive cultivar AK58 during germination using the polyethylene glycol (PEG) drought simulation method. An integrated analysis of the transcriptome and metabolomics was performed to understand the regulatory networks related to drought resistance in wheat germination and verify key regulatory genes.
Transcriptional and metabolic changes were investigated using statistical analyses and gene-metabolite correlation networks. Transcript and metabolite profiles were obtained through high-throughput RNA-sequencing data analysis and ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry, respectively.
A total of 8083 and 2911 differentially expressed genes (DEGs) and 173 and 148 differential metabolites were identified in AK58 and JM47, respectively, under drought stress. According to the integrated analysis results, mammalian target of rapamycin (mTOR) signalling was prominently enriched in JM47. A decrease in α-linolenic acid content was consistent with the performance of DEGs involved in jasmonic acid biosynthesis in the two cultivars under drought stress. Abscisic acid (ABA) content decreased more in JM47 than in AK58, and linoleic acid content decreased in AK58 but increased in JM47. α-Tocotrienol was upregulated and strongly correlated with α-linolenic acid metabolism.
The DEGs that participated in the mTOR and α-linolenic acid metabolism pathways were considered candidate DEGs related to drought resistance and the key metabolites α-tocotrienol, linoleic acid and l-leucine, which could trigger a comprehensive and systemic effect on drought resistance during germination by activating mTOR-ABA signalling and the interaction of various hormones.
中国冬小麦最高产区——华北平原，正遭受着严重的干旱威胁。传统的播种季灌溉方式浪费了大量的水资源。因此，研究小麦在萌发阶段的抗旱性，对于维护农业生态安全具有重要意义。本研究采用 PEG 干旱模拟法，从华北平原主要栽培品种中筛选出抗旱性品种 JM47 和抗旱性较弱的品种 AK58，利用转录组学和代谢组学的综合分析，解析小麦萌发过程中与抗旱性相关的调控网络，并对关键调控基因进行验证。
采用统计分析和基因-代谢物相关网络对转录组和代谢组变化进行分析。利用高通量 RNA-seq 数据分析和超高效液相色谱-四极杆飞行时间串联质谱分别获得转录和代谢物图谱。
在干旱胁迫下，AK58 和 JM47 中分别有 8083 个和 2911 个差异表达基因（DEGs），173 个和 148 个差异代谢物。综合分析结果表明，JM47 中雷帕霉素靶蛋白（mTOR）信号显著富集。在两个品种中，茉莉酸生物合成相关 DEGs 表现一致，α-亚麻酸含量降低。JM47 中的脱落酸（ABA）含量比 AK58 下降更多，而 AK58 中的亚油酸含量下降，JM47 中则增加。α-生育三烯酚上调且与 α-亚麻酸代谢强烈相关。
参与 mTOR 和 α-亚麻酸代谢途径的 DEGs 被认为是与抗旱性相关的候选 DEGs，关键代谢物α-生育三烯酚、亚油酸和亮氨酸通过激活 mTOR-ABA 信号和各种激素的相互作用，对萌发期抗旱性产生全面而系统的影响。
