Microbiome-Mediated Stress Resistance in Plants

Plants are subjected to diverse biotic and abiotic stresses in life. These can induce changes in transcriptomics and metabolomics, resulting in changes to root and leaf exudates and, in turn, altering the plant-associated microbial community. Emerging evidence demonstrates that changes, especially the increased abundance of commensal microbes following stresses, can be beneficial for plant survival and act as a legacy, enhancing offspring fitness. However, outstanding questions remain regarding the microbial role in plant defense, many of which may now be answered utilizing a novel synthetic community approach. In this article, building on our current understanding on stress-induced changes in plant microbiomes, we propose a ‘DefenseBiome’ concept that informs the design and construction of beneficial microbial synthetic communities for improving fundamental understanding of plant–microbial interactions and the development of plant probiotics. The recent advances in using synthetic communities together with metagenomics and metabolomics has begun to unravel mechanistic understanding of how stressed plants modulate their microbiomes.Stresses change plant transcriptomics and metabolomics below and above ground. Molecules such as flavonoids, coumarins, and other organic compounds have been recognized as plant signals that shape host microbiomes.A crucial regulating role of the interactions between the microbiome and plant immune system in stress tolerance is emerging. Experimental validation of such interactions and determination of how they influence plant fitness should now be prioritized.The plant-associated microbes that increase in abundance by plant stresses, coined the ‘DefenseBiome’, could benefit plant health and be used for designing functionally reliable synthetic communities to improve plant fitness.