The National Key Engineering Lab of Crop Stress Resistance Breeding, School of Life Sciences, Anhui Agricultural University, Hefei 230036, China.
Phytopathology. 2022 Sep;112(9):1886-1893. doi: 10.1094/PHYTO-01-22-0028-R. Epub 2022 Aug 1.
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.
种。在有效定植后，能发挥植物促生和生防作用，细菌对植物根分泌物的趋化性是定植的初始步骤。在生物胁迫下，植物能够改变其根分泌物，以吸引或避免不同类型的微生物。因此，病原体感染后对根分泌物的趋化性对于发挥其有益作用至关重要。在这项研究中，从 156 株根际微生物中筛选出对感染后玉米根分泌物表现出更强趋化能力的 OR2-30 菌株。进一步证实感染玉米根分泌物可提高 OR2-30 菌株的群集和生物膜形成能力。趋化性、群集和生物膜形成能力能够影响细菌的定植。事实上，OR2-30 菌株在感染后能更有效地在玉米根际定殖。接种。此外，OR2-30 产生的脂肽被鉴定为iturins，并能抑制的生长。进一步的研究表明，脂肽通过抑制分生孢子形成和萌发、诱导活性氧的产生以及导致菌丝细胞死亡来抑制的生长。最终，OR2-30 菌株提高了玉米对的抗性。这些结果表明，玉米根分泌物可以在感染后招募到，而通过产生脂肽，如iturins，来抑制，从而保护玉米。
