Isolation Of Bacterium And It’s Immunological Mechanism For The Plant Vaccin Against Tomato Bacterial Wilt Disease

The plant vaccine strain FJAT-1458, belonged to Ralstonia salanacearum FJAT-1458isolated from the tomato plant possessed with better control efficacy, larger colonization, longer colonization and steady biological characteristics on tomato bacterium wilt disease, were gained though the pathogenicity test and control effect test among the isolates of bacterium wilt disease in the tomato. The experiments were conducted with the colonization of plant vaccine inside the plant, the immunological mechanism of resistance to tomato bacterial wilt disease, the effects of plant vaccine on microbial population structure changed in the plant rhizosphere soil. The results showed as follows:1. The relationship between the incidence of tomato bacterial wilt disease and the inoculated concentration, the incidence of tomato bacterial wilt disease and the inoculated interval, as well as the plant vaccine and the virulent strain of Ralstonia salanacearum FJAT-91were analyzed using the plant vaccine strain FJAT-1458infected in the tomato plantlet. The result showed that the incidence of tomato bacterial wilt disease was associated with the inoculated concentration and the inoculated interval, the higher the inoculated concentration was, the shorter the interval was, the lower the incidence of the disease.2. The colonization of plant vaccine strain FJAT-1458inside the tomato plant and its rhizosphere soil was observed. The result showed that the strain FJAT-1458could colonize in the rhizosphere soil, the root and the stem, but could not in the leaf in the tomato. The inoculated concentration of strain FJAT-1458had significant effect on the amount of it colonized in the tomato plant and the rhizosphere soil. The higher the inoculated concentration was, the more the amount and the longer of the strain FJAT-1458was colonized in the plant and the soil.3. The effect of plant vaccine strain FJAT-1458on the protective enzyme system of tomato was analyzed. The results showed that the root length and dry weight and the plant height of tomato were not obviously affected by the plant vaccine FJAT-1458(P>0.05), but the activities of antioxidant enzymes were significantly affected. The total activities of POD, PPO and SOD at different parts of tomato plant in the treatments were significantly higher than that in the control. Moreover, the activity dynamics of POD, PPO and SOD were also significantly different between treatment and control.4. The effect of plant vaccine strain FJAT-1458on the microbial community structures in rhizosphere soils of several different crops including tomato, eggplant, peppers, towel gourd and celery was also measured. The result showed that the microbial PLFAs pattern and content in the rhizosphere soils of the crops mentioned above were changed under the stress of plant vaccine strain FJAT-1458. The alternation of microbial PLFAs could be divided three types, e.g. declining type, unchanging type and increasing type. The further analysis showed that the inoculation of strain FJAT-1458could change the microbial community structure in the rhizosphere soils of all these crops, by improving the growth of bacteria and fungi, inhibiting the reproduction of actinomycetes. The inoculation of strain FJAT-1458could changed the microbial community diversity in the soils, which enhanced Simpson index in the soils of towel gourd, tomatoes and celery, reduced Simpson index in the soils of eggplant and chili, enhanced Shannon index in soils of tomato and celery, reduced Shannon index in the soils of eggplant, peppers and towel gourd; reduced Pielou index in the soils of all these crops.5. The effect of root extractions of four crops(tomato, pepper, plantain banana, chive) on the growth of plant vaccine strain FJAT-1458were studied. The result showed that root extrations from different crops had different effect on the growth ability of strain FJAT-1458. The root extractions from tomato, pepper and plantain banana promoted the growth of strain FJAT-1458, while the root extractions from chive inhibited the growth of strain FJAT-1458. UV absorption spectrum analysis showed that strain FJAT-1458had no ultraviolet absorption peak in260nm and280nm when treated by root extraction of pepper and plantain banana for32h, however, the strain FJAT-1458had an ultraviolet absorption peak from250nm to300nm, when treated by root extraction of tomato and chive for32h. The colony morphology and attenuation index of strain FJAT-1458were not obviously different when treated by root extraction of different crops.