Benzoxazinoids and plant growth-promoting bacteria: A pathway to sustainable agriculture

Grass plants influence the composition of their rhizobiome through the secretion of metabolites, such as benzoxazinoids (BXs), which shape microbial communities. Paramount to plant health, the root associated microbiome may confer plant growth-promoting effects and tolerance to pathogens and herbivorous insects. Specifically, the BX derivative 6-methoxy-2-benzoxazolinone (MBOA), exhibits prolonged effects on soil microbiota and plant defense mechanisms by sustained biosynthesis and its relatively stable molecular structure. Leveraging Plant Growth-Promoting Rhizobacteria (PGPR) offers a sustainable strategy to enhance soil fertility and crop yield while reducing reliance on chemical inputs. However, the efficacy of microbial inoculants is contingent upon various factors, including cultivar and environmental conditions, necessitating tailored approaches for successful implementation. The ecological impact BXs as plant signaling molecules can have on microbial ecology is demonstrated by experiments on Fusarium strains. Conditioning soil with MBOA may offer a promising strategy to enhance the efficacy of microbial inoculation, thus improving environmental conditions and crop cultivation outcomes. In this review, we discuss how BXs can be used as a tool in sustainable agricultural practices. Therefore, the biochemistry of BXs; the mechanisms of PGPR involved in root colonization; and plant-soil feedback are discussed, offering insights into optimizing crop management for enhanced sustainability, yield and pest tolerance. • BXs shape root microbiomes and boost plant defense mechanisms • A host-specific effect of BXs on Fusarium demonstrates its ecological relevance • BXs soil conditioning can improve crop cultivation • Review explores BXs, PGPB, and feedback for sustainable crop