Analysis of the antagonistic effect of Stenotrophomonas geniculata WXY53 on Magnaporthe oryzae through bioassays and Whole-Genome sequencing

Abstract

Magnaporthe oryzae causes rice blast, which poses a significant threat to agriculture. The use of environmentally friendly biological control agents is one of the methods used to reduce disease incidence. Our study identified the isolate WXY53 as Stenotrophomonas geniculata using 16S rDNA and phylogenetic tree analysis. WXY53 exhibited a 53.39 % inhibition rate on the growth diameter of M. oryzae hyphae in the dual culture assay. The WXY53 fermentation broth treatment inhibited 97.89 % of appressoria formation and delayed the colonization of plant cells by invasive hyphae. Applying WXY53 fermentation broth had a significant impact on preventing rice blast in the greenhouse experiment. It suppressed the size of necrotic lesions and reduced the number of lesions in rice and barley by 66.25 % and 72.0 %, respectively. The whole-genome sequencing of WXY53 revealed a genome size of 4,504,923 bp, with 66.51 % GC content and 4038 protein-coding genes. The study utilized multiple databases, including the Kyoto Encyclopedia of Genes and Genomes, Clusters of Orthologous Groups of proteins, Gene Ontology, Pathogen-Host Interactions, and Carbohydrate-Active enZYmes to annotate gene functions. The analysis revealed genes related to environmental information processing, biological processes, cell wall/membrane/envelope biogenesis, glycoside hydrolases, and metabolism. Antibiotics & Secondary Metabolite Analysis Shell analysis predicted that WXY53 has the potential to produce aryl polymers, entolysin, and 2,3-dihydroxybenzoyl serine, in addition to the three gene clusters with unknown functions. Based on these findings, strain WXY53 could be a promising novel source of biological agents for managing rice blast. This study provides a theoretical basis for further investigation into microbial resources and metabolic gene clusters for agricultural biological control.