Biocontrol potential of Streptomyces albus G18 against anthracnose disease caused by Colletotrichum gloeosporioides in Camellia oleifera

Anthracnose of Camellia oleifera , caused by Colletotrichum gloeosporioides , infects the leaves and fruits of the host plant and inflicts substantial economic losses on the C. oleifera industry. Biocontrol using antagonistic microorganisms represents a key strategy for the green and sustainable management of this disease. In this study, a broad-spectrum antifungal strain G18 was isolated from soil samples and identified as Streptomyces albus through morphological characterization combined with whole-genome sequencing. Dual culture assays showed that strain G18 achieved an 85% inhibition rate against the mycelial growth of C. gloeosporioides on the 8th day, with a field control efficacy of 37.6%. Genomic analysis revealed that the genome of S. albus G18 contains multiple gene clusters involved in secondary metabolite biosynthesis, along with functional genes related to plant growth promotion, host colonization and pathogen defense. Further detection via widely targeted metabolomics demonstrated that the n-butanol extract of strain G18 fermentation broth constitutes the core material basis for its antifungal activity, with a total of 1297 metabolites identified. In conclusion, S. albus G18 exerts a moderate field control effect against C. oleifera anthracnose, making it a promising candidate biocontrol strain.