毛白杨内生菌优势种毛壳ND35室内拮抗作用的研究

TESTING ON THE ANTAGONISM OF THE DOMINANT OF ENDOPHYTIC FUNGI FROM POPULUS TOMENTOSA,CHAETOMIUM ND35 IN THE LABORATORY

对毛白杨内生真菌区系种群分析 ,筛选出优势种毛壳ND35 ,并测试了它对 6种常见林果病害病原真菌的拮抗作用。结果表明 ,毛壳ND35是一种广谱性拮抗菌 ,对供试的 6种病菌存在不同程度的抑制作用。可降低病菌菌丝的生长率和孢子的萌发率 ,并对小核菌的菌核进行重寄生 ,从而抑制其萌发。毛壳ND35的菌丝还产生吸器、附着枝等结构对立枯丝核菌 (Rhizoctoniasolani)等病菌的菌丝进行重寄生 ,在显微镜下可观察到病菌的菌丝被缠绕、穿透、断裂等现象。抑菌带和抑菌圈的产生证明抗生活动是毛壳ND35的主要拮抗作用机制之一。对活体毛白杨组培苗进行人工接种试验 ,结果用毛壳ND35预先接种的苗木发病率为零 ,明显低于只接烂皮病菌的对照发病率 5 3 33%,进一步证实了毛壳ND35对植物病害的生物防治潜能。

The dominant endophytic fungus Chaetomium ND35 was selected by analysing the components of endophytic flora from Populus tomentosa and its antagonism to 6 plant pathogens was evaluated in vitro and in vivo ,which included Macrophoma kuwatsukai,Valsa mali,Cytospora chrysosperma,Dothiorella gregaria,Rhizoctonia solani and Sclerotium rolfsii. The results showed that Chaetomium ND35 had antagonistic activities to all 6 species of tested plant pathogens. Chaetomium ND35 suppressed the mycerial growth and spore germination of pathogens.The sclerotia of S.rolfsii were hyperparasited and their germination rates were reduced.The facts that the inhibition zone was produced in dual culture with Cytospora spp.and the culture filtrates of Chaetomium ND35 inhibited the conidia germination of M.kuwatsukai and D.gregaria revealed that the antibiosis was a mode of action as mechanism of antagonism of Chaetomium ND35.The hyperparasitism was verified by the phenomena that the coiled,penetrated and disintegrated hyphae of R.solani were observed under the microscope.The result of artificial inoculation test with Chaetomium ND35 and C.chrysosperma also supplied the evidence for the potenciality of Chaetomium ND35 in biocontrol of plant diseases.