Antagonistic potential of lactobacillus plantarum against some postharvest pathogenic fungi

Abstract

Lactobacillus plantarum, one of the most widespread lactic acid bacte¬ria, exert a strong antagonistic activity against many microorganisms. The present study was conducted to determine in vitro and in situ antagonistic potential of L. plantarum (DSM 20174) for control postharvest decay caused by phytopathogenic fungi: Aspergillus flavus, Colletotrichum acutatum, Colletotrichum gloeosporioides, and Fusarium avenaceum. The results obtained in in vitro assays showed that L. plantarum had a stronger inhibitory effect on spore germination than on mycelia growth of all tested fungi. After 3 days of incubation, the diameter of inhibition zones ranged from 11.67 mm for C. gloeosporioides to 14.67 mm for C. acutatum. The bacterial suspension of L. plantarum significantly inhibited conidial germination of all postharvest pathogens (89.62-97.61%). In situ assays showed that treatment with L. plantarum efficiently inhibited necrosis ranging from 42.54% for C. acutatum to 54.47% for A. flavus. The disease incidence in L. plantarum treated fruits was statistically significantly lower than in the positive control for all fungi tested (P<0.05). The presented data demonstrate the antagonistic potential of L. plantarum (DSM 20174) and indicate the possibility of using this bacterial strain as a biological agent to control postharvest fungal pathogens.