Efficacy of aroma compounds for postharvest management of mango anthracnose

Abstract

Anthracnose is a severe disease of mango caused by Colletotrichum gloeosporioides Penz. The antifungal effects of the aroma compounds (trans-cinnamaldehyde, citral, and phenylacetaldehyde) were tested against the pathogen. These compounds exhibited complete inhibition of visual spore germination and the mycelial growth under in vitro conditions. Complete inhibition of mycelial growth of C. gloeosporioides was observed by trans-cinnamaldehyde (TCA) at 500 mg L−1 followed by citral (CT) at 750 mg L−1 and phenylacetaldehyde (PAA) at 2000 mg L−1. The effect of aroma compounds on the morphology and membrane lesion of C. gloeosporioides mycelia was studied through scanning electron microscopy (SEM). SEM observations revealed withered hyphae. Further experiments confirmed that aroma compounds inhibited the ergosterol synthesis and also triggered the membrane-active mechanism. Results on testing the efficacy of the aroma compounds through the fungal pectinase inhibition study confirmed that these aroma compounds have potential to damage plasma membrane integrity and cause membrane lesion of C. gloeosporioides, thereby causing the delayed anthracnose incidence in treated mango fruits as compared to control fruits. The antifungal activity of these aroma compounds could be attributed to the disruption of membrane integrity and leakage of cellular components. Results of the in vivo study showed that postharvest treatment of these compounds revealed that both disease incidence and severity efficiently managed in a dosage-dependent manner. The aroma compounds TCA, CT, and PAA might be an excellent natural and biodegradable bio-fungicides for the control of anthracnose disease in mango after harvest.