GREEN BIOCHEMICAL PROTECTION OF POSTHARVEST TABLE GRAPES AGAINST GRAY MOLD (BOTRYTIS CINEREA) USING 7S PROTEINS

Abstract

The 7S globulins (seed storage glycoprotein) isolated from soybean and chickpea seeds have the antifungal potential against the pathogenic fungus (Botrytis cinerea) causing gray mold in grapes assessing table grapes in vitro or postharvest by comparing with synthetic fungicide, Switch 62.5 WG. Conventional microbiological procedures estimated the in-vitro antifungal potential of the 7S globulins, such as linear growth curves and scanning electron microscopy (SEM). Soybean-7S significantly inhibited the in-vitro growth of Botrytis cinerea by about 64.44%, 66.64%, and 76.67% when applied at 50, 100, and 200 μg/mL, respectively, followed by chickpea 7S with growth reduction of 52.22%, 54.44%, and 66.67%, respectively. The synthetic fungicide (Switch 62.5 WG) induced higher growth inhibition extents (83.33% and 86.66%) when applied at 50 and 200 μg/mL, respectively. The 7S-exposed B. cinerea displayed swollen hyphae compared with the control under scanning electron microscope examination. The 7S derived from soybean and chickpea inhibited gray mold development in table grapes when applied at 200 and 400 μg/mL for 30 days after infection with B. cinerea. The maintained disease severity was also minimal (40% and 25% for soybean-7S and chickpea-7S, respectively). An increased level of treatment (400 μg/mL) highly reduced the disease severity to only 7.5% after 30 days of storage at cold conditions for both proteins. The 7S globulin from legume seeds can be an alternative to synthetic fungicides for controlling B. cinerea as a postharvest treatment. Developing these legume proteins as natural fungicides could also progress for the safe control of various plant pathogens, causing drastic crop losses.