Isolation And Identification Of Endophytic Fungi From Eucommia Ulmoides And Investigate The Colonization Of The Active Strain In Wheat

The research focused on two key themes of biological control—biocontrol resources and colonization in the rhizosphere and plants, and continued to isolate, identify and phylogenetic analyse the antagonistic endophytes isolated from the Eucommia ulmoides to clarify community characteristics of antagonistic endophytes. Then the colonization property of biocontrol strain DZJ07 in wheat was analysed to reaveal the colonization dynamics of biocontrol fungi in wheat rhizosphere and plant. Finally, the colonization of antagonistic endophyte DZJ07 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 32 fungi were isolated from leaves, stems and fruits of Eucommia ulmoides. The isolates were identified by morphological and molecular methods as belonging to 9 taxa:Nigrospora, Pestalotiopsis, Colletotrichum, Hypocreales, Phomopsis, Thielavia, Botryosphaeria, Alternaria and Myrothecium. The distribution of endophytic fungi presented tissue specificity in different tissues of Eucommia ulmoides. Among them, Pestalotiopsis and Hypocreales were isolated only from leaves. Thielavia and Botryosphaeria were only found to be colonized in fruits, while Nigrospora, Phomopsis and Colletotrichum were found in leaves, steams and fruits.2. Antifungal activity of 32 endophytic fungi were screened with 3 kinds of pathogenic fungi(Colletotrichum gloeosporioides, Gibberella zeae, 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 32 endophytic fungi had different inhibitions to three pathogenic fungi in vitro. Among them, DZGS07, DZGS01 and DZJ07 had strongest antagonistic activity to Colletotrichum gloeosporioides, Gibberella zeae and Rhizoctonia cerealis respectively. The results of pot culture experiments in greenhouse indicated that the control efficacy of DZGS07 against Colletotrichum gloeosporioides was 84.19%; The control efficacy of fermentation broth of DZGS01(2 mg.mL-1) against Gibberella zeae was 63.16%, which had no significant difference with the carbendazol wettable powder(diluted 800 times); The incidence of wheat which was treated by DZJ07 in Rhizoctonia cerealis was 13.36%, and which was obviously lower than control group(90.25%).3. The colonization of antagonistic endophyte DZJ07 in the rhizosphere and plant of wheat was detected with the method of tissue culture and aniline blue stains. The results indicated that DZJ07 had strong colonization ability in rhizosphere of wheat, then entered the body of wheat and conducted to steam by across the cortex of root. The activities of PPO, POD and PAL of wheat which were treated by colonization of DZJ07 in pot and 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 colonization of DZJ07 in wheat can significantly improve the activities of defense enzymes, while which increased the disease resistance of wheat to Rhizoctonia cerealis to some extent.