Antagonistic Potential of Bacillus Strain against the Post-Harvest Blue Mold of Lemon

Abstract

The present study focuses on the reduction of significant postharvest blue mold disease of lemon (Citrus limon L) fruit through the use of Bacillus strains in vivo and in vitro conditions. Blue mold which is caused by Penicillium italicum is the most dangerous postharvest disease of lemon fruit and causes significant losses in citrus fruits. In this study, antagonistic compounds like Cyclic lipopeptides (CLPs) produced by Bacillus strains were used to control P. italicum. CLPs are considered best the antagonistic compound of Bacillus Strains that primarily play an important role in the reduction of plant diseases and have three important families such as iturin, fengycin, and surfactin. This study was carried out by using seven strains of the genus Bacillus that were used in vitro assay. Among these seven strains, two strains Bacillus licheniformis and Bacillus thuringiensis showed wonderful inhibition zone in vitro assay carried out in Petri plates. Further CLPs were extracted from the both best strains and used in vivo assay on lemon fruit and showed less disease incidence and lesion diameter of disease. Furthermore, lemon fruits treated with CLPs showed increasing defense mechanisms of enzymes P AL, PPO, and PO. This study indicates the strong antifungal effect of Bacillus strains and their metabolites CLPs against the blue mold of lemon.