Maize Root Exudates Recruit OR2-30 to Inhibit Infection.

spp. can exert plant growth-promoting effects and biocontrol effects after effective colonization, and bacterial chemotaxis toward plant root exudates is the initial step to colonize. Under biotic stress, plants are able to alter their root exudates to attract or avoid different types of microbes. Hence, chemotaxis toward root exudates after pathogen infection is crucial for exerting their beneficial effects. In this study, the OR2-30 strain, which exhibited greater chemotaxis ability toward maize root exudates after infection, was screened from 156 rhizosphere microorganisms. The infected maize root exudates were further confirmed to improve the swarming and biofilm formation ability of the OR2-30 strain. Chemotaxis, swarming, and biofilm formation ability were able to influence bacterial colonization. Indeed, the the OR2-30 strain displayed more effective colonization ability in the maize rhizosphere after . inoculation. Moreover, lipopeptides produced by OR2-30 were identified as iturins and responsible for suppressing . growth. Further study showed that lipopeptides suppressed the growth of . by inhibiting conidia formation and germination, inducing reactive oxygen species production and causing cell death in mycelium. Eventually, the OR2-30 strain increased maize resistance against . . These results suggested that maize root exudates could recruit . OR2-30 after . infection, and that OR2-30 then suppresses the . by producing lipopeptides, such as iturins, to protect maize.