Screening and genomic analysis of biocontrol bacteria against cobweb disease of Oudemansiella raphanipes

Abstract:

Oudemansiella raphanipes is a rare edible and medicinal mushroom, while it is highly susceptible to cobweb disease caused by Cladobotryum varium.Objective To obtain bacteria capable of controlling cobweb disease and promoting the mycelial growth of O. raphanipes from casing soil.Methods Bacteria were isolated from the casing soil of O. raphanipes, and their antagonistic activity against the mycelial growth of both O. raphanipes and C. varium was evaluated. The strains with disease-preventing and growth-promoting properties were screened out, and their functioning mechanisms were studied based on genome data.Results A total of 90 bacterial strains were isolated from the casing soil, of which 38 strains showed significant inhibitory activity against the mycelial growth of C. varium and no inhibitory activity against that of O. raphanipes. The supernatants of two strains significantly inhibited the mycelial growth of C. varium and promoted that of O. raphanipes. Based on the genome data, the above two strains were identified as Peribacillus simplex and Ochrobactrum rhizosphaerae, respectively, and they carried multiple functional genes and biosynthetic gene clusters of secondary metabolites.Conclusion Two bacterial strains capable of controlling the disease and promoting the growth of edible fungi were obtained, providing valuable microbial resources for the future biocontrol of cobweb disease.