羧甲基壳聚糖诱导培养罗伦隐球酵母处理调控采后葡萄柚果实苯丙烷代谢及其抗青霉病作用

Regulation of Phenylpropane Metabolism and Resistance to Green Mold in Postharvest Grapefruits Treated by Carboxymethyl Chitosan-Induced Culture of Cryptococcus laurentii

为研究羧甲基壳聚糖(carboxymethyl chitosan,CMCS)诱导培养罗伦隐球酵母(Cryptococcus laurentii)处理对采后葡萄柚果实青霉病害的防控作用,以‘里约红’葡萄柚为试材,蒸馏水为对照,研究CMCS、C.laurentii单独处理和CMCS诱导培养C.laurentii(记为CMCS-C.laurentii)浸泡处理对葡萄柚果实青霉病害的防控效果及其对果实苯丙烷代谢的影响。结果表明,CMCS-C.laurentii处理显著抑制了葡萄柚果实青霉病发病率及病斑直径的扩展(P<0.05)。此外,与对照组相比,CMCS-C.laurentii处理提高了葡萄柚果实苯丙氨酸解氨酶、肉桂酸-4-羟基化酶、4-香豆酸辅酶A连接酶、多酚氧化酶、过氧化物酶、β-1,3-葡聚糖酶和几丁质酶活力以及总酚、类黄酮、木质素的含量。综上,添加CMSC诱导培养提高了C.laurentii的生防效力,CMCS-C.laurentii处理通过提高采后葡萄柚果实的苯丙烷代谢能力和抗性物质含量,从而增强葡萄柚果实抗青霉病效力,且CMCS-C.laurentii处理果实抗病效果优于CMCS、C.laurentii单独处理。

The purpose of this study was to investigate the effect of carboxymethyl chitosan(CMCS)-induced culture of Cryptococcus laurentii treatment on the resistance to Penicilium italicum in postharvest grapefruits.‘Rio Red’grapefruits were dipped in distilled water as a control,CMCS solution,C.laurentii suspension or CMCS-induced C.laurentii suspension.The biocontrol efficacy against green mold and phenylpropane metabolism in the treated grapefruits were analyzed.The results showed that the CMCS-induced C.laurentii treatment significantly reduced the disease incidence and lesion expansion of P.italicum in grapefruits(P<0.05).CMCS-induced C.laurentii treatment induced an increase in the activities of phenylalanine ammonia lyase(PAL),cinnamic acid 4-hydroxylase(C4H),4-coumaric acid coenzyme A ligase(4CL),polyphenol oxidase(PPO),peroxidase(POD),β-1,3-glucanase(GLU),and chitinase(CHI),and the contents of total phenols,flavonoids and lignin compared to the control group.Therefore,CMCS can induce increased biocontrol efficacy of C.laurentii.CMCS-induced C.laurentii can enhance the resistance to Penicilium italicum in postharvest grapefruits by increasing phenolpropane metabolism and resistance substance contents,and its effect is more pronounced than those of CMCS and C.laurentii.