Table_1_Regulation of soybean drought response by mepiquat chloride pretreatment.xlsx

IntroductionSoybean is the world’s most important cultivated crop, and drought can affect their growth and, eventually, yields. Foliar application of mepiquat chloride (MC) can potentially alleviate the damage caused by drought stress in plants; however, the mechanism of MC regulation of soybean drought response has not been studied.
MethodsThis study investigated the mechanism of soybean drought response regulation by mepiquat chloride in two varieties of soybean, sensitive Heinong 65 (HN65) and drought-tolerant Heinong44 (HN44), under three treatment scenarios, normal, drought stress, and drought stress + MC conditions.
Results and discussionMC promoted dry matter accumulation under drought stress, reduced plant height, decreased antioxidant enzyme activity, and significantly decreased malondialdehyde content. The light capture processes, photosystems I and II, were inhibited; however, accumulation and upregulation of several amino acids and flavonoids by MC was observed. Multi-omics joint analysis indicated 2-oxocarboxylic acid metabolism and isoflavone biosynthetic pathways to be the core pathways by which MC regulated soybean drought response. Candidate genes such as LOC100816177, SOMT-2, LOC100784120, LOC100797504, LOC100794610, and LOC100819853 were identified to be crucial for the drought resistance of soybeans. Finally, a model was constructed to systematically describe the regulatory mechanism of MC application in soybean under drought stress. This study fills the research gap of MC in the field of soybean resistance.

引言：大豆是全球最重要的栽培作物之一，干旱会影响其生长并最终降低产量。叶面喷施缩节胺（mepiquat chloride, MC）可潜在缓解植物干旱胁迫造成的损伤，但目前缩节胺调控大豆干旱响应的机制尚未见相关研究。
材料与方法：本研究以抗旱敏感型大豆品种黑农65（Heinong 65, HN65）和抗旱耐受型大豆品种黑农44（Heinong44, HN44）为实验材料，设置正常栽培、干旱胁迫、干旱胁迫+MC处理三种实验组，探究缩节胺调控大豆干旱响应的内在机制。
结果与讨论：缩节胺可在干旱胁迫下促进大豆干物质积累，降低株高，下调抗氧化酶活性，并显著降低丙二醛含量。光捕获过程以及光系统I、II均受到抑制，但缩节胺处理可促进多种氨基酸与黄酮类物质的积累并上调其表达水平。多组学联合分析显示，2-氧羧酸代谢途径与异黄酮生物合成途径是缩节胺调控大豆干旱响应的核心通路。本研究筛选出LOC100816177、SOMT-2、LOC100784120、LOC100797504、LOC100794610及LOC100819853等候选基因，这些基因对大豆抗旱性具有关键调控作用。最后，本研究构建了系统性模型以阐明干旱胁迫下缩节胺施用对大豆的调控机制，填补了缩节胺在大豆抗逆领域的研究空白。