Biocontrol Effect Of Endopbytic Fungi Isolated From Eucommia Ulmoides To Wheat Disease

The research focused on the theme of biocontrol resource exploitation,and continued to isolate,identify and phylogenetic analyse the antagonistic endophytes isolated from the Eucommia ulmoides oliv.to clarify community characteristics of antagonistic endophytes.Then treating antagonistic fungi in wheat rhizosphere,the microbial community dynamic change in wheat rhiosphere and wheat growth status were investigated,and further,the treatment of antagonistic endophyte in wheat and its effects on disease resistance of wheat were studied,which layed a foundation for improving the colonization ability and biocontrol efficacy of antagonistic endophytes.The research would expand our vision about the functional diversity and application of biocontrol microbial,which was of great significance to biological control of plant diseases.The main results were as follows:1.Systemically studied the distribution of endophytic fungi isolated from Eucommia ulmoides.A total of 52 fungi were isolated from leaves,stems and fruits of Eucommia ulmoides.The isolates were identified by morphological and molecular methods as belonging to 8 taxa: Nigrospora,Pestalotiopsis,Colletotrichum,Hypocreales,Phomopsis,Thielavia,Alternaria and Myrothecium.The distribution of endophytic fungi presented tissue specificity in different tissues of Eucommia ulmoides.Among them,Myrothecium was isolated only from leaves;Hypocreales and Alternaria were only found to be colonized in fruits,while Nigrospora,Pestalotiopsis,Phomopsis and Colletotrichum were found in leaves,steams and fruits.2.Antifungal activity of 52 endophytic fungi were screened with 3 kinds of pathogenic fungi(Fusarium graminearum,Gaeumannomyces graminis,Rhizoctonia cerealis)as tested targets by the methods of dual culture experiment on PDA plates and mycelial growth.The results showed that all of these 52 endophytic fungi had different inhibitions to three pathogenic fungi in vitro.Among them,DZJ14 had strongest antagonistic activity to Gaeumannomyces graminis and Rhizoctonia cerealis respectively.The results of pot culture experiments in greenhouse indicated that the disease index of DZJ14 against Rhizoctonia cerealis was 16.88%,the Disease index of DZJ14 against Gaeumannomyces graminis was 8.70 %,which were obviously lower than the disease index of control group 69.81 % and 50 % respectively.And the DZJ14 could promote wheat seeding plants growth.3.The microbial community dynamic change in wheat rhiosphere and wheat growth status were investigated by the concentration gradient method,The resultsshowed that the fungi community and bacteria community of wheat rhizosphere which was treatd with antagonistic fungi DZJ14 were obviously elevate and bacteria number less respectively than microbial community of control wheat rhizosphere,and the fungi community and bacteria community of wheat plant which was treatd with antagonistic fungi DZJ14 in wheat rhizosphere were obviously elevate and bacteria number less respectively than microbial community of control group.In addition,the activities of PPO,POD and PAL of wheat which with antagonistic fungi DZJ14 in wheat rhizosphere in field were detected by the method of spectrophotometer.The data showed that the activities of three defense enzymes in treatment groups were significantly higher than that of control groups.As a result,the treatment with DZJ14 in wheat rhizosphere can significantly improve the activities of defense enzymes,while which increased the disease resistance of wheat to Rhizoctonia cerealis and Gaeumannomyces graminis to some extent.