A novel peroxiredoxin from the antagonistic endophytic bacteriumEnterobactersp. V1 contributes to cotton resistance againstVerticillium dahliae

[Aims] To reveal the molecular mechanism of endophytic bacteria inVerticilliumwilt-resistant cottons and deeply understand the interaction between soil and plants. [Methods] Active tracking screening was used for the isolation of antagonistic strain. Morphological and molecular analyses were conducted to determine its phenotypic and genotypic characteristics. MALDI-TOF/TOF MS was employed to identify the antifungal substance. Functional verification was performed by gene cloning, expression, knockout and complementation. [Results]Enterobactersp. V1 was isolated fromVerticillium-wilt-resistant cotton Xinhai 15, which showed significantly antagonistic abilities against cotton verticillium wilt. A peroxiredoxin named ProV1 with virulent againstV. dahliaewas obtained. The gene for the peroxiredoxin ProV1 was cloned, and the nucleotide sequence showed 85.5% similarity with peroxiredoxin C (WP 096152328) reported fromE. hormaeche. The purified heterologously expressed ProV1 indicated strong inhibitory activities. Moreover, the suppression ofV. dahliaealso decreased in proV1 mutant strain compared with wild type strain. The inhibitory activities could be partially restored by a complementation of proV1 gene in the mutant strain. [Conclusion] The results of this study reveal that a novel peroxiredoxin from an endophytic bacterial strainEnterobactersp. V1 can serve as a virulent factor against fungiV. dahliae, which helps understanding the interaction between endyphytic bacteria and plant pathogenic fungi, and improving the biological control of cottonVerticilliumwilt.