Plant-microbiome responses under drought stress and their metabolite-mediated interactions towards enhanced crop resilience

The impacts of climate change are felt worldwide; however, drought stress poses significant challenges to global agriculture, affecting crop yields and food security. Understanding the multifaceted responses of crop plants to drought, particularly through their interaction with microbiomes and metabolites, is crucial and urgent for developing resilient agricultural systems. This review highlights the detrimental effects of drought on crop plants, including reduced water use efficiency, the production of free radicals, impaired plant growth and yield, and alterations in the photosynthetic apparatus. Additionally, this review addresses the research progress on plant responses, microbiome assemblages, metabolomic responses, and interactions under drought stress. By integrating findings from metabolomics, we discuss the “call for help” signal via root exudates in crop plants and their microbiomes during drought stress. Key aspects include the reciprocal exchange of metabolites (oxaloacetic acid, flavonoids, triterpenoids, phytoalexin, coumarin, and pyruvic acid), osmoprotectants (proline, sugars, amino acids), antioxidant enzymes (peroxidase, catalase, superoxide dismutase), and phytohormones (salicylic acid, jasmonic acid, and abscisic acid), along with the activation of stress-responsive pathways. Here, we explain the forefront of deciphering plant-microbiome interactions using cutting-edge metabolomics techniques. Therefore, this review summarizes the significance of metabolic and chemical exchanges between coexisting microorganisms to combat the escalating challenges of drought conditions effectively.