Modulation of plant chemistry by beneficial root microbiota

Plants are colonized by an astounding number of microorganisms that can reach cell densities much greater than the number of plant cells. Various plant-associated microorganisms can have profound beneficial effects on plant growth, development, physiology and tolerance to (a) biotic stress. In return, plants release metabolites into their direct surroundings, thereby feeding the microbial community and influencing their composition, gene expression and the production of secondary metabolites. Similarly, microbes living on and in plant tissue may induce known and yet unknown biosynthetic pathways in plants leading to diverse alterations in the plant metabolome. Here, we provide an overview of the impact of beneficial microbiota on plant chemistry, with an emphasis on bacteria living on or inside root tissues. We will also provide new perspectives on deciphering the yet untapped potential of microbemediated alteration of plant chemistry as an alternative platform to discover new pathways, genes and enzymes involved the biosynthesis of high value natural plant products.