Biosurfactant produced by Bacillus subtilis V26: a potential biological control approach for sustainable agriculture development

Abstract

Exploitation of microbial metabolites as biocontrol agents is considered an alternative to chemical pesticides in organic farming, due to their extensive potentiality in enhancing crop protection and food safety. The present work elucidates antifungal and insecticidal activities, exerted by the biosurfactant produced by the bacterial strain Bacillus subtilis V26 in order to provide protection against gray mold caused by Botrytis cinerea, in grapes and the tomato leaf miner Tuta absoluta. In vitro antifungal assay showed a minimal inhibitory concentration of about 2 mg mL−1, leading to the swelling and the deformation of fungal hyphae. In vivo assays with the grapes, the biosurfactant V26 exhibited a significant protection against gray mold severity especially as a protective treatment at concentration of 2 mg mL−1. The biosurfactant V26 also exhibited remarkable insecticidal activity against Tuta absoluta larvae (LC50 = 278.78 ng cm−2), causing histological damages in the larval midgut. This study demonstrated that the biosurfactant V26 has a potential as biocontrol agent against fungal disease and pest, which could be a promising biocontrol molecule for achieving organic agriculture.