Abstract:

The dominant endophy tic 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.

Key words: Chaetomium ND35, Populus tomentosa, Endophytic fungi, Antagonism, Hyperparasitism, Antibiosis