Study On Antibacterial Substances From Antagonistic Strains Against Tomato Bacterial Wilt

Bacterial wilt of tomato caused by Ralatonia solanacearum is an important disease which distributes widely in the world and it is very difficult to control. Plant endophytic bacteria have some superiority as biocontrol agents to control plant disease. Bucillus spp. can produce many kinds of antibacterial substances which can restrain or kill the pathogens. It is an important part of plant bio-control microbial. The tomato endophytic bacterias against Ralatonia solanacearum was used in the study to screen the strains with better controlling effect on tomato bacterial wilt and producing antibacterial substances. TR03-081 strain was found showing better repressing activity on Ralstonia solanacearum and high productivity of antibacterial substances. The producing condition and accumulation of antibacterial substances, the stability and the sort of antibacterial substances from TR03-081 strain, also the antifungal spectrum were studied furtherly. TR03-081 strain was identified in the last part of the study. The detailed experimental results are as follows.1. Five ones of ten strains (01-144, 01-189, TR03-081, TR03-108, TR03-124) showed better controlling effect on Ralstonia solanacearum in the experiment of plate culture. The result showed that disease-control efficiency of leavening of the above five strains was better than the bacterium on tomato bacterial wilt in greenhouse test, the disease-control efficiency of leavening of 01-189, TR03-108 and TR03-081 attained 53.85%, 65.38% and 50%, respectively. In the further plate culture experiment, the leavening of TR03-081 strain showed obvious controlling effect on Ralstonia solanacearum.2. The antibacterial substances from Bacillus subtilis TR03-081 strain showed unstability to high temperature, and it lost its antagonistic activity under 100℃ in 30min, good stability to 800Lx light, its antagonistic activity kept at the level of 88.62% after 36h treatment, partial stability to acid or alkali, unstability to high alkali condition, the antibacterial activity was impacted in the...