Interaction of plant-derived metabolites and rhizobiome functions enhances drought stress tolerance

Plants have evolved alongside microbes, enabling plants to better cope with abiotic and biotic stress. Interactions between plant roots and local soil microbes are critical for environmental adaptation and plant health. Plants actively regulate the microbial community composition in their rhizospheres to recruit specific microorganisms that enhance their fitness in the ecosystem they inhabit. This study builds on prior research suggesting that plants exhibit a "home field advantage" by preferentially recruiting microbes unique to their native environments, likely through mutual recognition and selective recruitment mechanisms.

Using gene- and genome-centric approaches, we assess the functional potential of root-associated microbes and profile their host metabolites to uncover the metabolic outputs potentially regulating host‒microbe interactions in Andropogon gerardii. We find that plants adapted to drier environments experience less stress, producing fewer stress-related metabolites and impacting the recruitment of microbes with genes linked to stress relief pathways. In particular, plant-derived trimethyllysine is highly associated with microbial populations capable of improving nutrient uptake, producing plant growth-promoting compounds, and modulating stress responses.

This study highlights the critical interplay between host exudates and microbial substrate uptake as the primary mechanism of rhizosphere assembly. We demonstrate that plants actively produce metabolites to recruit microbial populations with the functional potential to enhance their ability to thrive in stressful environments. This research provides insights into the mechanisms of plant-microbe communication, rhizosphere recruitment, and the complex interplay of plant-microbe interactions. Furthermore, it highlights promising avenues for manipulating rhizosphere microbiomes to support conservation agriculture when coping with climate change.