Insights into the Biocontrol Mechanisms of a Paenibacilluspeoriae Strain on Maize Seedling Blight through Multi-Omics Analysis

Maize seedling blight, caused by the phytopathogenic fungus Fusarium verticillioides, is a common and rapidly spreading disease that negatively impacts grain quality and productivity. Control of this pathogen is complicated by its complex infection process and the tendency for resistance to conventional chemical pesticides. The use of biological control agents has been recognized as an environmentally friendly and sustainable solution for the control of plant diseases. In our study, we isolated and identified Paenibacillus peoriae 3-B4 from maize leaves, which exhibited an inhibition rate of 59.92% against F. verticillioides in greenhouse experiments. Genome sequencing of P. peoriae 3-B4 revealed a chromosome of 5,912,131 bp, featuring a GC content of 45.51% on average and 5383 annotated coding sequences. Eight gene clusters associated with secondary metabolites with antifungal activity and thirteen genes associated with induced systemic resistance and pattern-triggered immunity were identified. Transcriptomic analysis identified 8,997 differentially expressed maize genes, with key defense genes (e.g., NPR1, bZIP, MYB, LRR, WRKY) enriched in MAPK signaling and plant-pathogen interactions. 16S rRNA analysis showed significant shifts in microbial communities, particularly with an increase in the abundance of beneficial genera like Paenibacillus, Delftia, and Corynebacterium. The combined analysis of differentially expressed genes and microbial communities indicated that they synergistically enhance pathogen resistance in maize. Our findings outline the potential mechanisms by which P. peoriae 3-B4 inhibits F. verticillioides infection and open possibilities of exploiting biological control strategies to control maize seedling blight.