槐糖脂对蜜橘果实采后青霉病的控制及其机理

Biocontrol of Postharvest Blue Mold(Penicillium italicum) on Satsuma Mandarin(Citrus unshiu Marc.)Fruit by Sophorolipid and Underlying Mechanism

从自然发病的蜜橘果实上分离出一株致病真菌,通过形态学特征、rDNA-内转录间隔区(rDNA-internal transcribed spacer,rDNA-ITS)分析以及致病性检测,发现该真菌为柑橘意大利青霉(Penicillium italicum)。离体实验发现,当槐糖脂质量浓度为0.1 g/L时,青霉的生长被完全抑制;在果实实验中,当槐糖脂质量浓度为35 g/L时,蜜桔果实的病斑直径最小,且发病率最低。采用质量浓度为35 g/L的槐糖脂对蜜桔果实进行接种和浸泡处理,均能有效提高蜜桔果实的抗病性,且蜜桔果皮的过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶的活力得到了提高。该实验为蜜桔果实采后青霉病的防治提供了一定的理论依据。

A pathogenic fungal strain was isolated from naturally infected satsuma mandarin fruit.On the basis of morphological characteristics,rDNA-internal transcribed spacer(rDNA-ITS)sequence analysis and pathogenicity test,the pathogen was identified as Penicillium italicum.The in vitro test showed that the growth of Penicillium italicum was completely inhibited at a sophorolipid concentration of 0.1g/L;in the fruit test,the smallest lesion diameter and the lowest incidence of blue mold were observed at a sophorolipid concentration of 35g/L.Treatment with 35g/L sophorolipid effectively enhanced disease resistance in inoculated satsuma mandarin fruit by increasing the activities of peroxidase(POD),polyphenol oxidase(PPO)and phenylalanine ammonialyase(PAL).Our experimental results offer a theoretical basis for the prevention and control of postharvest blue mold in satsuma mandarin fruit.