2种昆虫病原线虫共生菌的代谢产物对苹果病原菌真菌的抑菌作用

嗜线虫致病杆菌(Xenorhabdus nematophila HB310)和发光杆菌(Photorhabdus luminescens HB140)是分别从小卷蛾斯氏线虫和异小杆线虫中分离到的2株昆虫病原线虫共生菌。为了明确这2种共生菌的抑菌活性,分别测定了其对苹果上6种主要病原真菌的抑菌活性。结果表明,这2种共生菌对6种苹果病原真菌均有不同程度的抑制作用。嗜线虫致病杆菌HB310菌株发酵液对苹果轮纹病病原菌抑制效果最好,抑制率达76.9%,对其他病原菌的抑制作用依次为苹果树腐烂病病原菌(74.1%)>苹果斑点落叶病病原菌(60.9%)>苹果灰霉病病原菌(46.7%)>苹果青霉病病原菌(44.5%)>苹果炭疽病病原菌(23.0%);发光杆菌HB140菌株发酵液对苹果灰霉病病原菌的抑制作用最好,抑制率达到86.7%,对其他病原菌的抑制作用依次为苹果树腐烂病病原菌(76.6%)>苹果轮纹病病原菌(58.8%)>苹果斑点落叶病病原菌(46.0%)>苹果青霉病病原菌(44.2%)>苹果炭疽病病原菌(39.9%)。2种共生菌发酵液对苹果轮纹病菌均有较强的抑制作用,其EC50分别为42.28和42.92 mL/L。

Antifungal activity of metabolites from Xenorhabdus nematophila and Photorhabdus luminescens against apple pathogenic fungi

Xenorhabdus nematophila HB310 and Photorhabdus luminescens HB140 were isolated from the nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora respectively.According to bioassay of their antifungal activity against 6 major fungi species in apple,the results showed that both symbiotic bacteria had different antimicrobial activities against 6 species fungi.X.nematophila HB310 had a best antimicrobial activity against Botryosphaeria berengeriana f.sp.piricola(Nose) Koganezawa et Sakuma and mycelial growth inhibitory rate was reached to 76.9%,and inhibitory rates of it against other pathogenic fungi were respectively(from high to low): 74.1%(Valsa Mali)﹥60.9%(Alternaria mali Roberts)﹥46.7%(Botrytis cinerea)﹥44.5%(Penicillium expansium)﹥23.0%(Glomerella cingulata).P.luminescens HB140 had a best antimicrobial activity against Botrytis cinerea and the mycelial growth inhibitory rate was 86.7%.The inhibitory rates of it against other pathogenic fungi were respectively(from high to low): 76.6%(Valsa Mali)﹥58.8% B.berengeriana.f.sp.piricola)﹥46.0%(Alternaria mali Roberts)﹥44.2%(Penicillium expansium)﹥39.9%(Glomerella cingulata).EC50 of two symbiotic bacteria X.nematophila HB310 and P.luminescens HB140 against B.berengeriana de Not.f.sp.piricola were 42.28 mL/L and 42.92 mL/L respectively.