| Endophytic bacteria is a kind of microbial resources that variety, widely used in plant research(promoting plant growth, disease resistance, etc.), easy to colonization and play a lasting role. For screening excellent disease resistance and to promote endophytic microorganisms used on ecological forest in Shanghai, this paper we isolation the endophytic bacteriafrom the three species of camphor,cherry, metasequoia glyptostroboides with tissue sections and tissue homogenate.Screening of strains with antagonistic action against plant pathogens or have the ability of phosphorus fixing nitrogen fixation in the isolated endophytic bacteria.Identification the excellent bacteria that we screening.At the same time, the salt tolerance of the strains was studied.Using the green fluorescent protein gene marker to study colonization laws of excellent strain in the tree.In addition, we selected the excellent strains that screened by the former in my laboratory use to ecological forest in Shanghai for analysis of the effect of strain on the growth promoting effect of disease resistance in field.The main results are as follows:1.We separated 50 bacteria and 3 fungi from camphor organized.Through the flat experiments we screened 5 antagonistic strains that can against the fusicoccin canker pathogen(Fusicoccum sp.), 6 antagonistic strains that can against the pestalotia deadwood Pathogen(Pestalotiopsis sp.) and 9 antagonistic strains that can against the phomopsis canker pathogen(Phomopsis sp.).Among them, the strain ZS-37 and the strain ZS-3 have antagonistic effect on all three kinds of pathogenic bacteria,the strain ZS-1 had antagonistic effect on two kinds of pathogenic bacteria(Fusicoccum sp. and Phomopsis sp.),the strains ZS-26 and the strain ZS-30 had antagonistic effect on two other kinds of pathogenic bacteria(Phomopsis sp. and Phomopsis sp.).We separated 32 bacteria from the cherry blossoms. Through the flat experiments we screened 2 antagonistic strains that can against the agrobacterium(Agrobacterium tumefaciens) and the strain numbers were YH-18 and YH-20.We separated the 22 bacteria and 3 fungi from organization of Metasequoia glyptostroboides. Through the flat experiments we screened 1 antagonistic strains that can against the Alternaria tenuissima. 2 antagonistic strains that can against the Pestalotiopsis heterocornis among them, the strain SS-15 have antagonistic effects on two kinds of pathogenic bacteria.2.By analyzing the phosphate dissolving ability of the isolated strain.The results showed that there were 8 strains endophytic bacteria in the isolated strains, strain numbers were YH-18, YH-20, ZS-1, ZS-37, ZS-28, SS-4, SS-1 and SS-15, respectively.At the same time, we found that all of the PH of fermentation broth of strain after 24 h had decreased.We screened 7 strains with nitrogen fixation. Strains numbered were YH-32, ZS-47,SS-15, YH-18, SS-1, ZS-37 and ZS-28, respectively.The experimental that the salt tolerance of endophytic bacteria results show that: all of isolated strains were able to survive under the conditions of 5% sodium chloride,some strains can survive under the condition of 10% sodium chloride,all strains were unable to survive under the condition of 15% sodium chloride. These 10 strains of endophytic bacteria that we screening of can adapt to the saline soil. They can survive in the soil environment of Shanghai City, which is beneficial to the further promotion of the later stage.3.The selected strains YH-18, ZS-37 and SS-15 as the excellent strains were identified.The results showed that the three strains were Bacillus methylotrophicus, Bacillus anthracis and Bacillus Vanillea, respectively.4.We Studied the colonization rule of 3 candidate strains in camphor, cherry and metasequoia respectively by green fluorescent protein labeling methodon.Marked strains were successfully constructed,the stability of marked strain are reached about 93%.The marked strains were successfully observed in the root tissues of the three tree species. |
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