Genetic determinants of Brevundimonas-mediated attenuation of plant pattern-triggered immunity

TonB1 is the strongest genetic determinant of immune attenuation by the root-associated commensal Brevundimonas sp. MF374, with ppiD contributing more weakly.

• Why it matters: Root commensals can attenuate plant PTI, but the bacterial genes and mechanisms driving this immune attenuation are not well defined.
• What they did: The study screened 4,032 MF374 transposon mutants for loss of attenuation, then used deletion/complementation and GUS reporter assays to test flg22 and AtPEP1 responses.
• The result: Intact MF374 cells directly reduced flg22 immune-eliciting activity in a tonB1-dependent manner, and TonB1 also contributed to attenuation of responses to a distinct flg22 sequence and endogenous AtPEP1.