Effects of melatonin treatment on resistance to Aspergillus carbonarius in postharvest'Cabernet Sauvignon'grape
To investigate the impact of melatonin(MT)on the resistance of grape(Vitis vinifera)fruit to As-pergillus(subgenus Circumdati,section Nigri),this experiment utilized'Cabernet Sauvignon'grape as the experimental material.Melatonin was applied through pre-harvest spraying and post-harvest soaking methods to treat grape fruit,aiming to preliminarily explore the mechanisms by which two melatonin treat-ments enhance the resistance of grape fruit to Aspergillus.The results indicate that melatonin effectively increased the resistance of grape fruit to Aspergillus.Pre-harvest spraying with 150 μmol·L-1 melatonin significantly reduced the incidence of post-harvest fruit compared to the control.However,the in vitro inhi-bition of A.carbonarius mycelial growth by melatonin at concentrations of 100-200 μmol·L-1 was not pro-nounced.Post-harvest treatment with 150 μmol·L-1 melatonin resulted in a 30.7%reduction in the inci-dence rate compared to the control group when inoculated with A.carbonarius.The combined pre-harvest and post-harvest treatment with 150 μmol·L-1melatonin not only reduced fruit mass loss but also increased the activities of disease-related enzymes in grape fruit.It elevated the levels of secondary metabolites in the phenylpropanoid pathway,including total phenols,flavonoids,and lignin.In conclusion,the combined pre-harvest and post-harvest melatonin treatment can enhance the resistance of grape fruit to Aspergillus by increasing the activities of disease-related enzymes and the contents of secondary metabolites.