Inhibitory effect and mechanism of nitric oxide (NO) fumigation on fungal disease in Xinjiang Saimaiti dried apricots

Abstract

Nitric oxide (NO) is a gaseous free radical molecule that is widely used for controlling postharvest diseases in fresh fruit. However, there have been few reports on its application in dried fruit. In this study, the inhibitory effect of NO on disease in dried apricots caused by Aspergillus flavus, Aspergillus niger and Penicillium italicum was investigated both in vivo and in vitro. Furthermore, the inhibitory effect of NO and sulfur dioxide (SO2) on the three fungi was compared in vitro. NO fumigation decreased the severity of disease in dried apricots in vivo and suppressed colony expansion and mycelial growth of the three fungi in vitro in a concentration-dependent manner. The antifungal activity of NO was similar or better than that of SO2in vitro. Further, Mechanistic studies showed that NO reduced mycelium biomass, increased cell membrane permeability, destroyed plasma membrane integrity, and changed the mycelium microscopic structure. The damage of the fungal cell membrane induced by NO fumigation inhibited fungal growth and reproduction. Our results demonstrate that NO plays a critical role in controlling fungal disease in Xinjiang Saimaiti dried apricots.