Pseudomonas from Potato Inhibited the Pathogenicity of Verticillium nonalfalfae through the BCAA Biosynthesis Pathway

Verticillium wilt severely impacts potato production,
necessitating
eco-friendly control strategies. This study used 16S sequencing to
analyze bacterial communities in potatoes and fungi before and after
inoculation with Vn011, the Verticillium wilt pathogen. Inoculation
increased Pseudomonas abundance in
potato stems from 0.26% to 1.64%. Importantly, Pseudomonas was absent in the long term laboratory-maintained fungal strain
Vn011 but represented 90.95% of the bacterial community in the freshly
isolated fungal strain Vn011potato from potato plants.
Therefore, a Pseudomonas simiae strain, Ps4, isolated from Vn011potato, was found to
inhibit Verticillium nonalfalfae, promote
potato growth, and reduce the disease index from 0.9 to 0.09 in coinoculation
assays. Transcriptome analysis suggested that Ps4
suppresses Vn011 by targeting its branched-chain amino acid (BCAA)
biosynthesis pathway, with growth inhibition reversed by BCAA supplementation.
This study reveals P. simiae as a promising
biocontrol agent against potato Verticillium wilt and highlights the
BCAA pathway as a novel target for disease management.