VdNPS, a Nonribosomal Peptide Synthetase, Is Involved in Regulating Virulence in Verticillium dahliae

Abstract

Nonribosomal peptide synthetases (NPS) are known for the biosynthesis of antibiotics, toxins, and siderophore production. They are also a virulence determinant in different phytopathogens. However, until now, the functional characterization of NPS in Verticillium dahliae has not been reported. Deletion of the NPS gene in V. dahliae led to the decrease of conidia, microsclerotia, and pathogenicity. ΔVdNPS strains were tolerant to H2O2, and the genes involved in H2O2 detoxification, iron/copper transport, and cytoskeleton were differentially expressed in ΔVdNPS. Interestingly, ΔVdNPS strains exhibited hypersensitivity to salicylic acid (SA), and the genes involved in SA hydroxylation were up-regulated in ΔVdNPS compared with wild-type V. dahliae under SA stress. Additionally, during infection, ΔVdNPS induced more pathogenesis-related gene expression, higher reactive oxygen species production, and stronger SA-mediated signaling transduction in host to overcome pathogen. Uncovering the function of VdNPS in pathogenicity could provide a reliable theoretical basis for the development of cultivars with durable resistance against V. dahliae-associated diseases.

Synergistic Plant-Microbe Interactions between Endophytic Actinobacteria and Their Role in Plant Growth Promotion and Biological Control of Cotton under Salt Stress

“…Cotton disease severity was classified into four grades according to visible symptoms on cotyledons and true leaves as follows: 0 (no symptoms), 1 (>0–25% yellowing or wilting leaves), 2 (25–50% yellowing or wilting leaves), 3 (50–75% yellowing or wilting leaves), and 4 (75–100% yellowing or wilting leaves) [ 60 ]. The disease index (DI) (%) represents a comprehensive and objective measure of plant health, with high DI values corresponding to serious infection by V. dahliae .…”

Bacillus circulans GN03 Alters the Microbiota, Promotes Cotton Seedling Growth and Disease Resistance, and Increases the Expression of Phytohormone Synthesis and Disease Resistance-Related Genes

“…The disease index was calculated by assessing 30 individual plants per treatment and repeated three times with the following formula: disease index = (number of disease leaves × disease grade)/(total number of leaves × 4) × 100. The disease grade was classified as follows: 0 (no symptoms), 1 (>0-25% yellowing or wilting leaves), 2 (25-50% yellowing or wilting leaves), 3 (50-75% yellowing or wilting leaves), and 4 (75-100% yellowing or wilting leaves) (Luo et al, 2020). The assessment was performed every 3 days for 21 days post inoculation (dpi) V991.…”