Biological control for basal rot in yellow pitahaya fruits (Selenicereus megalanthus): Ex vivo trials

Abstract

Endophytic microbiome for biocontrol of plant pathogens has been the subject of recent research. Fusarium oxysporum (F54) and Fusarium fujikuroi (F17) are fungi associated with basal rot in yellow pitahaya fruits (Selenicereus megalanthus), which limits the possibilities of fruit commercialization. ObjectiveIn this study, the ability of Lactobacillus plantarum (endophytic bacterium), Weissella cibaria (non-endophytic), and their metabolites to control the basal rot of yellow pitahaya (caused by fungi F54 and F17) was evaluated. MethodsHealthy yellow pitahaya fruit was sprayed with lactic acid bacteria or their metabolites, and one hour later, spore solutions of F54 and F17 were individually injected into the fruit peduncle. The affected area of the peduncle was measured at 15 days. The percentage of the area of infection was measured using image evaluation software. The percentage reduction of infection was also calculated. Results: When healthy fruits were inoculated with pathogens (positive control), these developed a severe disease (more than 14 cm2 of infection). Healthy fruits sprayed with W. cibaria and L. plantarum or their metabolites (negative control without pathogens) remained healthy for more than 15 days. Treatments without lactic acid bacteria began with symptoms of senescence on day 9. L. plantarum (and its metabolites) reduced the manifestations of basal rot in yellow pitahaya fruits by up to 99.99%. ConclusionsSpecific microbiome of yellow pitahaya as L. plantarum is an effective biological control agent against Fusarium associated with basal rot. L. plantarum and its metabolites could reduce the environmental impact caused by synthetic fungicides used to control basal rot of yellow pitahaya. Finally, the results of this research suggest that a fungal consortium may not be necessary to develop the basal rot disease.