Effect of chlorogenic acid on controlling kiwifruit postharvest decay caused by Diaporthe sp.

Chlorogenic acid (CGA) is a phenolic compound derived from plants that has anti-microbial activity. Effect of CGA toward Diaporthe sp. infection in kiwifruit was evaluated in the present study. Results demonstrated that fungal spore germination, germ tube elongation, and mycelial growth were all significantly inhibited by CGA. Exposure of Diaporthe sp. to CGA induced a reactive oxygen species (ROS) burst, which was mediated by an influx of calcium, resulting in mitochondrial dysfunction and apoptosis. The response of fungal cells of Diaporthe sp. to CGA included the activation of the calcium/calmodulin signaling pathway. Postharvest application of CGA induced defense-related enzyme activity in kiwifruit and inhibited Diaporthe sp. infection in a concentration dependent manner. CGA also contributed to the maintenance of fruit quality during storage. Collectively, our results suggest that CGA effectively inhibits the growth of Diaporthe sp. by inducing mitochondrial oxidative stress, which is mediated by calcium influx and by inducing defense-related enzyme activity in kiwifruit. The result of this collective effect was a significant reduction on the postharvest decay in kiwifruit.