Biocontrol of Colletotrichum fructicola in the Postharvest Banana Fruit Using the Siderophore-Producing Strain BX1.

Banana anthracnose, caused by Colletotrichum fructicola, significantly reduced the postharvest fruit quality. Employing biocontrol strategies offers a sustainable approach to enhance agricultural practices. The Burkholderia sp. strain BX1 hinders the growth and appressorium formation of C. fructicola, and its sterile filtrate lowers the anthracnose incidence while preserving the fruit quality. Scanning electron microscopy and genomic analyses confirmed BX1 as Burkholderia pyrrocinia. AntiSMASH analysis identified three siderophores with high similarity, and improved MALDI-TOF IMS confirmed the presence of the siderophore pyochelin. Furthermore, the BX1 filtrate suppressed the expression of virulence genes in C. fructicola and induced the expression of disease resistance genes in banana. However, the presence of 80 μM iron ions notably mitigated BX1's inhibitory effects and reversed the changes in related gene expression. These results underscore BX1's robust efficacy as a biocontrol agent in managing banana anthracnose, highlight the effective antifungal compounds, and elucidate the influence of environmental factors on biocontrol effectiveness.