Characterization of Lasiodiplodia brasiliensis causing banana black rot in Korea and its biocontrol by Paraburkholderia busanensis P39 through volatile-mediated microbiome modulation

Post-harvest diseases significantly reduce fruit quality and storage longevity, necessitating sustainable management strategies. In this study, we identified Lasiodiplodia brasiliensis as the causative agent of black rot in bananas in South Korea, marking the first confirmed report in the region. Morphological and multi-locus phylogenetic analyses were performed for precise species identification. Given the increasing need for biological control solutions, the antagonistic activity of Paraburkholderia busanensis P39 against L. brasiliensis was investigated through direct and volatile-mediated interactions. Dual-culture assays demonstrated strong anti-fungal activity of P39 against the pathogen, whereas mycophagy assays further revealed its ability to exploit fungal mycelia as a nutrient source. In addition to direct inhibition, P39 volatiles significantly suppressed black rot symptoms in bananas without physical contact and effectively extended the fruit shelf life. A microbiome analysis of banana peels treated with P39 volatiles was performed to elucidate the underlying mechanisms. Metabarcoding of the bacterial and fungal communities revealed distinct microbial communities, including the enrichment of Paraburkholderia and suppression of spoilage-associated bacteria (Pseudomonas and Enterobacter). Fungal community analysis indicated a significant increase in the abundance of yeast-like fungi, suggesting a microbiome-mediated contribution to fruit preservation. Correlation analysis further supported the role of P39 volatiles in the restructuring of microbial interactions, leading to enhanced disease suppression and delayed ripening. These findings highlighted the dual functionality of P39 volatiles in pathogen inhibition and fruit preservation, positioning them as promising residue-free alternatives for post-harvest disease management. This study provides critical insights into the microbiome-driven mechanisms underlying biological control and offers a foundation for the development of microbial-based post-harvest preservation strategies.