Abstract: The objective of this work was to investigate the inhibitory effect of L-cysteine on brown rot caused by Monilinia fructicola on postharvest plum fruit. We explored the in vitro inhibitory effect and possible mechanism of L-cysteine at various concentrations (1, 10, 100 and 1 000 mg/L) on M. fructicola, and we further explored its effect on the control of postharvest brown rot on plum fruit induced by stab inoculation. The results showed that only 1 000 mg/L L-cysteine treatment could significantly delay the spore germination, inhibit the mycelial growth of M. fructicola, increase the membrane permeability and the leakage of intracellular nucleic acid, and destroy the cell membrane integrity (P < 0.05). Moreover, L-cysteine treatment at 1 000 mg/L could reduce disease incidence and lesion diameter in wounded and inoculated plum fruit when compared with the control fruit (P < 0.05), while at the other concentrations it had no significant effectiveness against brown rot on postharvest plum fruit.

Key words: L-cysteine, postharvest, plum fruit, Monilinia fructicola, inhibitory effect