Isolation And Screening Of Endophytes From Tomato And Rape And Their Antagonistic Activity To Plant Pathogens

Antagonistic screening of endophytes from tomato and rape collected from different regions of Shanxi province, and growth promoting activity of endophytic bacteria to tomato plant were surveyed. Inhibitory activity of metabolic substances of antagonistic strains was studied. Identification of the strains and antagonistic mechanism to Botrytic cinerea were also carried out. 1. Ninty-five bacterium strains,25 fungus strains and 8 actinomycete strains were isolated from tomato and rape plants, and antagonistic screening of endophytes were carried out. Results indicated that in tomato and rape plants, bacterium isolates were dorminant, followed by fungus isolates, actinomycete isolates were feeble. Numbers and species of endophytes varied with different varieties of tomato and different parts of tomato, i.e. there were more endophytic fungi in the stems than in the roots for the same cultivars, while there were more endophytic bacteria in the roots than in the stems. Some endophytes showed strong antagonistic activities by dual-culture tests. Endophytic bacterium strains fq12 and yc8 demostrated strong antagonistic activities to six pathogens, especially to Botrytis cinerea and Sclerotinia sclerotiorum. There were wider inhibition zones between strain fq72 and six pathogens respectively. Endophytic actinomycetes manifested weak antagonistic activity. 2. Results on inhibitory activities of metabolic substances from antagonistic endophytes indicated that after treated with a high temperature, the fermentation solution of two strains fq12 and yc8 showed strong antibiosis activities against B. cinerea and S. sclerotiorum, and certain activities to other four pathogens. Results on growth promoting activity of endophytic bacteria to tomato indicated that more bacteria didn't affect germination rates and growth. Some strains, however, showed significant growth promoting effects. Two strains fq65 and fq29 can increase seedling sprout, growth and also fresh and dry weights. 3. Endophytic fungi from tomato were identified. one strain was indentified as Saccharomyces sp. belonged in Ascomycetes, while other 18 strains belonged in Imperfecti. Antagonistic bacteria were also identified. Fq12,yc8 and fq25 belonged in Pseudomonas,Bacillus and Staphylococcus respectively,other 5 strains belonged in Enterabacteriaceae.