Screening And Bioactivity Evaluation Of Antagonistic Endophytic Fungi From Camellia Sinensis

Tea is an important economic crop.However,the continuous occurrence of diseases and pests seriously endangers tea production.Among them,tea anthracnose(Gloeosporium camellia sinensis Miyake)and tea grey blight(Pestealota camellia Sawada)are two important tea leaf diseases,which will cause a large reduction in tea production.For a long time,chemical control has been the main means to deal with tea plant diseases.However,due to the increasingly prominent shortcomings that it is easy to cause pathogen resistance,pollute the ecological environment and threaten human health,tea plantations urgently need a sustainable plant disease control technology,while biocontrol agents can control tea plant diseases while causing minor harmful effects on the environment.The mechanisms of tea endophytic fungi against biological stress mainly include the secretion of antibacterial substances,the competition of nutrients and niche with pathogens,and the induction of plant systemic disease resistance.In addition,tea endophytic fungi can produce a variety of bioactive metabolites,and have a long-term coevolutionary relationship with tea plants.They are environmentally friendly and do no harm to the growth of tea plants.They are ideal biological control resources for tea pathogenic fungi.Therefore,this paper will study the screening and biological activity evaluation of tea antagonistic endophytic fungi.The conclusions are as follows:(1)20 endophytic fungi were isolated and purified from the root,stem and leaf tissues of Shuchazao tea plants by tissue isolation and grinding dilution methods.(2)7 antagonistic endophytic fungi of tea plants were screened and identified through the plate confrontation experiment with Colletotrichum gloeosporioides and pseudopestalotiopsis camellia.Among them,two fungi of the genera Irpex lacteus and Penicillium ehrlichii were isolated from tea plants for the first time.(3)Through the plate confrontation experiment with a variety of common plant pathogenic fungi,it was found that three endophytic fungi No.19,No.11 and No.9.with antagonistic activity against a variety of plant pathogenic fungi(4)The fermentation broth of a highly effective antagonistic strain No.19 was prepared and its antibacterial activity under different fermentation conditions was evaluated.It was clear that its antibacterial effect was the best under the fermentation time of 3 days,and its antibacterial activity was positively correlated with the concentration of fermentation broth.(5)The pot experiment was conducted to evaluate the control effect of spraying No.19 fermentation broth to prevent tea anthracnose and tea grey blight.It was found that it was better than the recommended dose of carbendazim,which provided a research basis for the application of biocontrol endophytes.