Evidence for the plant recruitment of beneficial microbes to suppress soil-borne pathogen

Abstract

SummaryEmerging experimental framework suggests that plants under biotic stress may actively seek help from soil microbes, but empirical evidence underlying such a ‘cry for help’ strategy is limited.We used integrated microbial community profiling, pathogen and plant transcriptive gene quantification and culture-based methods to systematically investigate a three-way interaction between the wheat plant, wheat-associated microbiomes and Fusarium pseudograminearum (Fp).A clear enrichment of a dominant bacterium, Stenotrophomonas rhizophila (SR80), was observed in both the rhizosphere and root endosphere of Fp-infected wheat. SR80 reached 3.7×107 cells g-1 in the rhizosphere and accounted for up to 11.4% of the microbes in the root endosphere. Its abundance had a positive linear correlation with the pathogen load at base stems and expression of multiple defense genes in top leaves. Upon re-introduction in soils, SR80 enhanced plant growth, both the below- and above-ground, and induced strong disease resistance by priming plant defense in the aboveground plant parts, but only when the pathogen was presentTogether, the bacterium SR80 seems to have acted as an early warning system for plant defense. This work provides novel evidence for the potential protection of plants against pathogens by an enriched beneficial microbe via modulation of the plant immune system.