Table 4_Overexpression of Umellularia californica FatB thioesterase affects plant growth and lipid metabolome leading to improved drought tolerance in Arabidopsis and tomato.xlsx

Frequent and extreme drought exerts profound effects on vegetation growth and production worldwide. It is imperative to identify key genes that regulate plant drought resistance and to investigate their underlying mechanisms of action. Long-chain fatty acids and their derivatives have been demonstrated to participate in various stages of plant growth and stress resistance; however, the effects of medium-chain fatty acids on related functions have not been thoroughly studied. Here, we integrate lipidomic, transcriptomic, and genetic analyses to elucidate the roles of the medium-chain acyl-acyl carrier protein thioesterase of Umellularia californica FatB (UcFatB) in drought tolerance and plant growth. Arabidopsis and tomato transgenic lines overexpressing UcFatB showed that the medium chain fatty acids mainly affect the male reproductive process of plant development. Transcriptomic and non-targeted lipid metabolomic combination analysis revealed significant changes in lauric acid-related metabolic pathways, as evidenced by increased phosphatidylcholine accumulation and upregulated stress-response gene expression. Consistent with the thicker waxy cutin layer and increased membrane integrity, UcFatB-overexpression enhanced drought tolerance in both Arabidopsis and tomato. Furthermore, methyl laurate and phosphatidylcholine application improved tomato drought resistance and fruit yield. These findings provide new insights into the potential genetic resources and cost-effective chemicals for enhancing drought resistance in crops.

频发且极端的干旱对全球植被生长与生产力造成深远影响。鉴定调控植物抗旱性的关键基因并探究其潜在作用机制，实为当务之急。长链脂肪酸及其衍生物已被证实参与植物生长与抗逆响应的多个阶段，但目前关于中链脂肪酸在相关功能中的调控作用仍有待深入系统研究。本研究整合脂质组学（lipidomic）、转录组学（transcriptomic）与遗传学分析手段，旨在阐明加州月桂（Umellularia californica）FatB基因（UcFatB）编码的中链酰基-酰基载体蛋白硫酯酶在植物抗旱性与生长发育中的功能。通过对过表达UcFatB的拟南芥与番茄转基因株系开展分析，发现中链脂肪酸主要参与调控植物发育过程中的雄性生殖发育进程。转录组学与非靶向脂质代谢组学（non-targeted lipid metabolomic）联合分析显示，月桂酸相关代谢通路发生显著改变，具体表现为磷脂酰胆碱（phosphatidylcholine）积累量升高，抗逆响应基因表达量上调。过表达UcFatB可使拟南芥与番茄的蜡质角质层更厚、细胞膜完整性更高，这与其抗旱性显著提升的表型相一致。此外，外源施加月桂酸甲酯与磷脂酰胆碱可有效提升番茄的抗旱性与果实产量。本研究结果为开发可用于提升作物抗旱性的潜在遗传资源与低成本化学制剂提供了全新的研究视角。