PDF(Pubmed)
Abstract：
Postharvest decay of goji berries, mainly caused by Alternaria alternata, results in significant economic losses. To investigate the effects of melatonin (MLT) on resistance to Alternaria rot in goji berries, the fruits were immersed in the MLT solutions with varying concentrations (0, 25, 50, and 75 μmol L-1) and then inoculated with A. alternata. The results showed that the fruits treated with 50 μmol L-1 MLT exhibited the lowest disease incidence and least lesion diameter. Meanwhile, endogenous MLT in the fruits treated with 50 μmol L-1 MLT showed higher levels than in the control fruits during storage at 4 ± 0.5 °C. Further, the enzymatic activities and expressions of genes encoding peroxidase, phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, 4-coumarate-CoA ligase, chalcone synthase, chalcone isomerase, and cinnamyl alcohol dehydrogenase were induced in the treated fruit during storage. UPLC-ESI-MS/MS revealed that secondary metabolites in the fruits on day 0, in order of highest to lowest levels, were rutin, p-coumaric acid, chlorogenic acid, ferulic acid, caffeic acid, naringenin, quercetin, kaempferol, and protocatechuic acid. MLT-treated fruits exhibited higher levels of secondary metabolites than the control. In conclusion, MLT treatment contributed to controlling the postharvest decay of goji fruit during storage by boosting endogenous MLT levels, thus activating the antioxidant system and secondary metabolism.
摘要：
采后枸杞腐烂,主要由链格孢菌引起,造成重大经济损失。研究褪黑素(MLT)对枸杞抗链格孢菌腐病的影响,将果实浸入不同浓度（0、25、50和75μmolL-1）的MLT溶液中，然后接种A。结果表明，用50μmolL-1MLT处理的果实发病率最低，病变直径最小。同时,在4±0.5°C储存期间，用50μmolL-1MLT处理的果实中的内源MLT显示出比对照果实中更高的水平。Further,过氧化物酶编码基因的酶活性和表达，苯丙氨酸氨裂解酶，肉桂酸4-羟化酶，4-香豆酸-CoA连接酶,查尔酮合成酶，查尔酮异构酶，处理后的果实在贮藏过程中诱导肉桂醇脱氢酶。UPLC-ESI-MS/MS显示，第0天水果中的次生代谢产物，按最高到最低的顺序，是芦丁，对香豆酸,绿原酸,阿魏酸,咖啡酸,柚皮苷,槲皮素,山奈酚,和原儿茶酸。MLT处理的果实表现出比对照更高的次生代谢产物水平。总之,MLT处理有助于通过提高内源MLT水平来控制枸杞果实在贮藏过程中的采后腐烂，从而激活抗氧化系统和次生代谢。
