Genome Sequence, assembly and characterization of Bacillus velezensis VR-34 used as biocontrol agent of Peyronellaea arachidicola (peanut web blotch, Pathogen)

Abstract

Peyronellaea arachidicola, a fungus that specifically targets the foliage of peanut plants, causes web blotch disease, which has an impact on the crop's yield and quality. In the present study, Whole-genome sequencing identified and characterized Bacillus velezensis VR-34, as a biocontrol antagonistic strain. In vitro assay showed that VR-34 had a significant antagonistic effect on P. arachidicola with an inhibition zone of 90.39 mm, which was higher than the inhibition zone of 80.45 mm for Ck. In greenhouse assay, in the pre-inoculated treatment, it was observed that the VR-34 strain exhibited a biocontrol efficacy of 93.52% against peanut web blotch disease, whereas the control group showed a biocontrol efficacy of 95.64%.. However, in the post-inoculated treatment, it was observed that the VR-34 strain exhibited a biocontrol efficacy of 89.89% against peanut web blotch disease, whereas the control group showed a biocontrol efficacy of 88.71%. The SEM analysis revealed that VR-34 caused damaged the hyphal surfaces and broken of spores of P. arachidicola. Whole-genome sequencing revealed twenty functional groups from 2833 annotations in the COG database, most of which were involved in transcription, secondary metabolite biosynthesis, amino acid transport and metabolism, and carbohydrate metabolism. 1694 KEGG annotations link 33 metabolic pathways. Glycoside hydrolases, glycosyl transferases, carbohydrate esterases, auxiliary activities, carbohydrate-binding modules, and polysaccharide lyases were among the 172 annotations in the CAZy database. antiSMASH analysis predicted that strain VR-34 can produce the secondary metabolites difficidin, aurantinin, elansolid, basiliskamide macrobrevin, kalimantacin, sowinholide A, bacillaene, and calyculin. In vitro, and greenhouse studies revealed that VR-34 controlled peanut web blotch disease. The whole genome study showed the VR-34 strain is B. velezensis and could synthesize antifungal secondary metabolites.