Evaluating drought impact on white cabbage: Plant stress response and soil microbiome adaptation

Abstract

Drought is a dangerous abiotic stress, worsened by climate change, that threatens agriculture by reducing yields, degrading soil, and hindering plant growth. Since the soil microbial community has great potential to mitigate the negative effects of drought, research into how these bacterial communities adapt to drought and interact with plants is increasingly important for sustainable agriculture. In this study, 27-day old white cabbage (Brassica oleracea var. capitata f. alba) plants were exposed to a 13-day drought conditions. Following the treatment, we assessed the plant's stress response by evaluating its morphology, yield, photosynthetic parameters, pigment levels, stress markers, and mineral content. Additionally, changes in the soil microbiome were monitored through 16S rRNA amplicon sequencing and measurements of microbial enzyme activity. Plants under drought stress showed reduced growth and photosynthetic activity, along with increased stress markers compared to controls, confirming activation of stress response mechanisms. In contrast, the soil microbiome demonstrated greater resilience, maintaining stable community diversity despite the drought conditions. Notably, a decrease in the abundance of Gemmatimonadota was observed, along with an increase in arylsulfatase activity in drought-stressed soils. Our results emphasise the complexity of interactions between soil, microorganisms and drought, highlighting that plants are generally more sensitive to drought than their associated soil microbiomes. These results could serve as a valuable basis for future studies focused on screening and understanding the role of drought-tolerant bacteria that could provide potential solutions to improve crop resilience.