Transcriptomic analysis revealed the alleviating effects of exogenous GABA on soybean seedlings responses to manganese toxicity

Mn stress severely affects plant growth and production. GABA exerts important roles in defensing abiotic stresses, while studies on the involvement of GABA in regulating soybean responses to Mn stress are relatively rare. In this study, integrated biochemical and transcriptomic analyses were conducted to explore the effects of GABA on soybean responses to Mn stress. Our results showed that an appropriate application of exogenous GABA could migrate the Mn toxicity by activating antioxidant enzyme activities, altering amino acid metabolism and affecting the distribution of mineral element in leaves. Gene co-expression regulatory network analysis showed that a transcriptor factor, GmNAC022, was identified as a hub gene in GABA-mediated soybean Mn tolerance. Yeast-one-hybrid analysis verified that GmNAC022 could bind the promoters of target genes, such as peroxidases, glutathione-S-transferase and metal tolerance protein, to regulate their expression. Collectively, our findings not only provide some insights into the mechanism by which GABA improves soybean Mn stress tolerance, but also provide some new strategies for the proper application of GABA in agricultural production.

锰胁迫会严重损害植物生长与作物产量。γ-氨基丁酸（GABA）在抵御非生物胁迫中发挥着关键作用，但目前针对GABA调控大豆响应锰胁迫的相关研究仍较为匮乏。本研究通过整合生化与转录组学分析手段，探究了GABA对大豆响应锰胁迫的调控效应。研究结果显示，外源施加适宜浓度的GABA可通过激活抗氧化酶活性、调控氨基酸代谢以及影响叶片内矿质元素分布，从而缓解锰胁迫毒性。基因共表达调控网络分析表明，转录因子GmNAC022是GABA介导的大豆锰胁迫耐受通路中的核心枢纽基因。酵母单杂交（Yeast-one-hybrid）实验验证了GmNAC022可结合过氧化物酶、谷胱甘肽S-转移酶以及金属耐受蛋白等靶基因的启动子区域，进而调控这些基因的表达。综上，本研究结果不仅阐明了GABA提升大豆锰胁迫耐受能力的潜在分子机制，同时也为GABA在农业生产中的合理施用提供了全新的应用策略。