Benzothiadiazole (BTH) is a functional analog of salicylic acid (SA), and has been applied to delay postharvest decay in several fruit. However, the efficacy of BTH on delaying postharvest decay of litchi fruit and involved regulatory mechanisms remained unknown. Physiological, microbiological, and metabolomic analyses were applied in this study to reveal efficacy and potential mechanism of BTH on the control of postharvest litchi downy blight. Our results showed that BTH enhanced the disease resistance of litchi fruit against downy blight in vivo. The in vitro test indicated that BTH treatment markedly inhibited the mycelial growth and sporangia germination of Peronophythora litchii. Enzyme activity assay revealed that BTH treatment enhanced the activities of CAT, SOD, PPO and PAL in litchi fruit. Moreover, the expression levels of senescence-related genes were down-regulated by BTH treatment. A comparative metabonomic analysis showed that metabolites accumulation significantly affected by BTH treatment, especially amino acids contents of arginine, phenylalanine and glutamic acid increased in comparison with control group. In all, the inhibitory effect on pathogen, the blocked transcription of senescence-related genes, and the activation of defense enzymes and amino acid metabolism induced by BTH treatment might be attributed to the alleviation effect of BTH on postharvest litchi downy blight. These findings indicated that BTH might be a potential agrochemical to control postharvest litchi downy blight and extend shelf life of litchi fruit.

苯并噻二唑 (BTH) 是水杨酸 (SA) 的功能类似物，已被用于延缓多种水果的采后腐烂。然而，BTH延迟荔枝果实采后腐烂的功效和相关调控机制尚不清楚。本研究通过生理学、微生物学和代谢组学分析揭示了 BTH 对荔枝采后霜霉病的防治效果和潜在机制。结果表明，BTH在体内增强了荔枝果实对霜霉病的抗病性。在体外试验表明，BTH处理明显抑制菌丝生长和孢子萌发霜疫荔枝. 酶活性测定表明，BTH处理提高了荔枝果实中CAT、SOD、PPO和PAL的活性。此外，BTH 处理下调了衰老相关基因的表达水平。比较代谢组学分析表明，BTH处理显着影响代谢物的积累，尤其是精氨酸、苯丙氨酸和谷氨酸的氨基酸含量与对照组相比有所增加。总之，BTH处理对病原菌的抑制作用、衰老相关基因的转录受阻、防御酶的激活和氨基酸代谢的激活可能与BTH对荔枝采后霜霉病的缓解作用有关。