Antifungal activity of dimethyl trisulfide and potential biocontrol against Alternaria alternata on postharvest Lycium barbarum

Abstract Lycium barbarum , is a medicine-food homology plant, so sustainable control of the postharvest Goji berry black mold caused by Alternaria alternata is particularly critical. In this paper, the impact of dimethyl trisulfide (DMTS) on A. alternata was studied, as well as the effects of DMTS on hypha ultrastructure, membrane permeability, reactive oxygen production, and essential enzymes of the cellular defense system. DMTS was shown to significantly inhibit the spore germination and hyphal growth of A. alternata in a concentration-dependent manner. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that A. alternata cells were separated between cytoplasm and cell wall, organelles such as mitochondria were vacuolate or even disappeared, and the cytoplasm was fused. PI staining, conductivity measurements, and intracellular nucleic acid and protein content measurements showed that the permeability of the cell membrane changed after DTMS treatment, leading to the leakage of intracellular nucleic acid and protein. DMTS could also cause the accumulation of hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA), thus causing membrane oxidative damage. Through directly destroying the fungal cell and indirectly inducing membrane damage, DMTS can control the postharvest Goji berry black mold, and is a potential application prospect in the control of postharvest diseases.