Inhibitory of grey mold on green pepper and winter jujube by chlorine dioxide (ClO2) fumigation and its mechanisms

As a powerful sanitizer, chlorine dioxide (ClO2) has mainly focused on control of bacteria, but little is known about its antifungal effects, especially on postharvest fungi found in vegetable and fruit. This study investigated the effect of ClO2 on Botrytis cinerea growth in vitro and on its disease severity in green pepper and winter jujube. Result showed that ClO2 fumigation reduced disease development of grey mold caused by B. cinerea on green pepper and winter jujube, and the efficiency was positively correlated with ClO2 concentrations. ClO2 treatment directly inhibited mycelial growth, spore germination and germ tube elongation of B. cinerea. To further survey the mechanisms by which ClO2 treatment inhibited hypha growth of B. cinerea, we observed the mycelial morphology and the integrity of the plasma membrane; the results showed that ClO2 treatment resulting in B. cinerea mycelial morphology was strongly affected, and leading to the loss of plasma membrane integrity, causing the cellular leakage. These data showed that ClO2 was effective for controlling grey mold caused by B. cinerea on green pepper and winter jujube, and the antifungal activity of ClO2 could be attributed to the disruption of cell membrane of the fungal pathogen.