Phytohormonal and metabolomic responses to Lysinibacillus sp. TT41 and lactic acid during drought stress in kimchi cabbage (Brassica rapa L. subsp. pekinensis).

Abstract

Drought-stress severely disrupts plant metabolism and nutritional quality. We investigated the metabolic and hormonal mechanisms underlying drought tolerance in kimchi cabbage treated with Lysinibacillus capsici TT41 and its metabolite, lactic acid (LA). Comprehensive profiling revealed 84 metabolites and 9 hormones, distinguishing drought-stressed plants from surviving plants. Notably, 10 mM LA treatment effectively maintained metabolic homeostasis, resulting in profiles comparable to those of controls. This finding demonstrates that LA modulates the accumulation patterns of nitrogenous metabolites, thereby enhancing drought tolerance while preserving the crop's nutritional quality. A strong correlation between these metabolites and key stress hormones (abscisic acid, jasmonic acid, and salicylic acid) suggests that LA is closely associated with the coordinated modulation of an integrated metabolic-hormonal network that maintains chemical homeostasis. These findings highlight LA as a promising chemical elicitor for preserving the nutritional quality of cruciferous vegetables and provide a sustainable strategy to maintain food quality under environmental-stress.