| In this study, 302 endophytic bacteria strains were isolated for the first time from the roots,stems and leaves of the wild and cultivated schisandra(Schisandra chinensis) which collected from different areas in Jilin Province. using plate confrontation method, JYg07 and CYg11 were found with strong antagonism effect against more than 10 kinds of pathogenic microrganisms infecting S chinensis. JYg07 and CYg11 were systematically researched, and the main results are as follows:1. The results showed that there were large amounts of endophytic bacteria in the roots,stems and leaves of S. chinensis. The numbers of endophytic bacteria from S. chinensis are different from the collected areas: wild schisandra collected from Ji’an city(4.70×104cfu/gfw) > wild schisandra collected from Changbai county(3.96×104 cfu/gfw) > cultivated schisandra collected from Changbai county(3.47×104 cfu/gfw)> cultivated schisandra collected from Ji’an city(2.66×104 cfu/gfw)> cultivated schisandra collected from Zuojia town,Jilin city(2.46×104 cfu/gfw). The numbers of endophytic bacteria in different parts of schisandra are also different,: the overall trend of roots > stems > leaves.2. 77 antagonistic strains being of antagonism activity to 10 kinds plant pathogenic fungi were screened out from 302 endophytic bacteria by plate confrontation method. All 77 strains were of antagonistic activity to more than one pathogenic fungus and with a wider antimicrobial spectrum. The quantity of antagonistic bacteria in cultivated schisandra is varied with the collected areas: Changbai > Ji’an > Zuojia, while Ji’an city> Changbai county in wild schisandra. In the meanwhile, the number of antagonistic bacteria are significant different in the different parts, the trend is roots > stems > leaves.3.Based on the effects of bacteriostasis, 12 strains with strong antagonistic activity to one or several tested pathogens were choosed to further experiments. The results suggested that fermented liquid of 12 endophytic bacteria strains have strong antibacterial activity to different tested pathogens, There were difeerent antibacterial activity and different bacteriostatic spectrums to different pathogens among different strains,. In conclusion, JYg07 and CYg11 are the excellent antagonistic endophytic bacteria from S. chinensis being of broad-spectrum and inhibitory effects.4. According to the morphological, physiological and biochemical characteristics, as well as analysis of 16 SrDNA sequences, JYg07 and CYg11 were were identified as B. thuringiensis and B. cereus, respectively.5. Using antibiotic notation method, mutant strains of JYg07 and CYg11 resistant to streptomycin and Rifampin at same time were obtained, and their colonization in different parts of S.chinensis was tested in the meantime. The results indicated that the labeled strains of JYg07 and CYg11 could colonize and engraft rapidly in schisandra, and the colonization ability in root was higher than in stems and leaves. High concentration of nutrient solution method and root irrigation method can make JYg07 and CYg11 in the best colonization state in schisandra,which providing a foundation for control diseases.6. Effect of the culture liquid, bacterial suspension and fermented filtration of JYg07 and CYg11 against Fusarium oxysporum were compared. The results suggested that JYg07 and CYg11 had inhibitory effect on the growth of mycelium and spore germination. Among of them,the inhibitory effect of their culture solution on spore germination s was the best(JYg07, 91.5%and CYg11, 93.4%). The results in greenhouse showed that the control effect of strain broth was the best, and the effect was improved with time. And on the 15 th day, the inhibitory rates were89.00% and 87.73%, respectively. While, the control effects of JYg07 and CYg11 were more lower in fields than in greenhouse, and their average control effects were only 38.61% and28.47%, respectivly.7. The growth ofschisandrawas significantly promoted by JYg07 and CYg11. Especially,CYg11 can promote the growth rates of plant height, stem diameter and root length of S.chinensis to 18.4%, 51.6% and 20.1%, respectively. While, growth rate of JYg07 were 15.6%,35.4% and 6.7%, respectively. In addition, the growth of tomato and pepper were significantly promoted by CYg11 and JYg07.8. The multifactor and orthogonal experiments indicated that starch, peptone and0.5%NaCl are the most important factors for CYg11’s growth. The optimized cultured conditions of the endophytic bacteria was identified by further single factor experiments as:initial pH was 7.0, inoculation amount was 3%, liquid volume was 50 mL/250 mL, culture temperature was 30℃, speed was 150 r/min, and the optimal age of the bacteria was between32 h and 72 h. Under this condition, the largest OD600 value of the fungi was 1.94 and the inhibitory rate was 84.2%. |
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