Isolation and control of Botrytis cinerea in postharvest green pepper fruit

Botrytis cinerea is a necrotrophic fungus that causes severe losses of postharvest pepper fruit. Moreover, this fungus is indiscriminate, causing severe disease in a variety of plant species, thus isolation and identification of the individual strains are crucial for the development of strain specific antifungal agents. In this study, B. cinerea was isolated from naturally infected green pepper fruit and identified through morphological features, pathogenic symptoms and rDNA-ITS analysis. The antifungal potential of the food additive sodium dehydroacetate (SD) and plant natural product trans-2-hexenal (TH) against the isolated pathogen was then examined. Sequence alignment and phylogenetic tree analysis matched the isolated strain to B. cinerea strains previously isolated from infected sweet pepper in Pakistan, and homology alignment analysis showed that it was 100% homologous to strain NRCB07. In vitro and in vivo experiments showed that both SD and TH treatments strongly inhibited the growth of the isolated B. cinerea, SD had a concentration dependent effect, while TH had an obvious antifungal effect only at higher concentrations. Both SD and TH limited the progression of gray mold disease and reduced the weight loss and respiration rate of inoculated green peppers. Treated pepper retained higher levels of Vc, chlorophyll and total soluble solids. SD and TH also enhanced the activities of the antioxidant enzymes SOD, POD and CAT of pepper, which may be directly responsible for the delayed onset of gray mold disease. Taken together, these results suggest that SD and TH are potential antifungal agents against B. cinerea and can be considered for the health control of gray mold in postharvest green peppers.