Isolation And Screening Of Endophytic Actinomyces Fq24 And Preliminary Study On Its Bioactivities

Fifteen endophytic actinomyces strains were isolated from healthy plants of tomato, pepper and sunflower collected from Taigu, Linfen, Yuncheng in Shanxi Province. Strain Fq24 having strong antagonistic effect on Botrytis cinerea Pers. was screened out through dual-culture and inhibitory activity test.1. Combining morphology and some physiological and biochemical characters, we identified Fq24 as S. graminearus var. rectus Yen&Lu. Through dual-culture with plant pathogens, Fq24 was found having antagonistic effect against B. cinerea, Sclerotinia sclerotiorum de Bary, Fulvia fulva (Cooke) Cif. and Colletotrichum gossypii Southw. Fermentation solution of Fq24 had significant inhibitory effect on B. cinerea and S. sclerotiorum and inhibitory-rate was 68.4% and 88.2% separately.2. The optimum fermentation media components were 2% glucose, 2% soybean powder, 3% corn powder, 1% starch, 0.1% beef extract, 0.2% KNO3, 0. 2%NaCl, 0.03%MgSO4, 0.6% CaCO3, 0. 02% KH2PO4, initial pH 6. 5. Culture condition were inoculation dose 1%, content 100mL/500mL flask, temperature 28℃, rotate speed 160rpm, culture time 7d.3. Result of bioactivities of metabolites of Fq24 showed that (1) At lower concentrations Fq24 could promote germination of tomato seeds and growth of seedlings while at higher concentrations they were prohibited. (2) POD and SOD activities of tomato plants treated with Fq24 fermentation solution were higher than control, which suggested that Fq24 could induce the increase of POD and SOD activities. (3) Pot test against B. cinerea indicated that Fq24 could significantly reduce disease occurrence of tomato gray mould and had the best control effect (88.14%) while B. cinerea was inoculated 48 hours after inoculation of Fq24.