Drought-driven shifts in Eucommia ulmoides rhizosphere mycobiota and metabolites mediate host tolerance

Drought poses considerable challenges to the sustainable development of crops, highlighting the urgent need to improve plant resistance to drought stress. Rhizosphere mycobiota roles in Eucommia ulmoides drought adaptation remain uncharacterized. This study examines E. ulmoides' rhizosphere mycobiota diversity, its changes, and interactions with plant physiology and metabolites under drought stress using amplicon sequencing, plant physiological assessments, and non-targeted root metabolomics. Our data indicate that drought stress considerably altered the species richness and community composition of the E. ulmoides seedling rhizosphere mycobiota, affecting the co-occurrence patterns and the composition of core fungal taxa within the mycobiota. Additionally, Sordariomycetes were notably enriched in the rhizosphere of E. ulmoides under drought stress and showed a notable positive correlation with the physiological indicator soluble sugar (SS). During drought stress mid-stages, rhizosphere core fungal taxa of E. ulmoides exhibit higher diversity, increased network connectivity, and a tighter network structure. Correlation analyses show that core fungal taxa are significantly linked to malondialdehyde (MDA) content. The root metabolome's phosphatidylcholines (o-16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) and 8-demethyltetracenomycin C are also notably affected by the core microbial taxa. In summary, drought stress drives changes in the E. ulmoides rhizosphere mycobiota, plant physiology, and root metabolites, with MDA, SS, and 8-demethyltetracenomycin C possibly mediating the selection of specific rhizosphere fungal communities. Taken together, these data provide notable insights into plant-microbe interactions under drought stress and have important implications for improving the drought adaptability of E. ulmoides.IMPORTANCEDrought presents substantial challenges to the sustainability of crops, highlighting the need to enhance their resistance to arid conditions. Although the rhizosphere microbiome plays a crucial role in bolstering crop resilience, the dynamics and mechanisms of Eucommia ulmoides' rhizosphere mycobiota under drought conditions remain poorly understood. This study provides valuable insights into the interactions between plants and microbes under drought stress and has significant implications for improving the drought adaptability of E. ulmoides.