Studies On The Population And Dynamic Analysis Of Tomato Endophytic Bacterium And Its Inhibition To Tomato Bacterial Wilt

Two hundred and seventy symptomless tomato plants were collected for analysis of the population and dynamic of endophytic bacterium from Wuming, Tianyang, Yuling and guilin of Guangxi. Five hundred and seventy-one strains were obtained. The genera of tomato endophytic bacterium were Bacillus spp.,Pseudomonas spp., Xanthomonas spp., Microbacterium spp.,Corynebacterium spp. andAgrobacterium spp.. The dominated genera of tomato endophytic bacterium was Bacillus spp..Tomato endophytic bacteria varied with the organs, growth periods ,regions and varieties. The variety of Hongbaoshi NO. 1 could not found Corynebacterium spp.in the root of tomato, and Microbacterium spp. did not live in the stems of the plants. But the kinds of endophytic bacteria had not any difference in the organs of variety of Meixing. The population of most endophytic bacteria in the growth periods of tomato increased firstly and then reduced, but Microbacterium spp. and Corynebacterium spp. reduced gradually. The main genera of endophytic bacteria were Bacillus spp.,Pseudomonas spp. and Agrobacterium spp. in defferent regions. Excepting these three main groups, there were Xanthomonas spp. , Corynebacterium spp. , Microbacterium spp and Erwinia spp. in the tomato plants of Tianyan . By the comparision with the tomato endophytic bacteria of Tianyang, there was not Erwinia spp. in the tomato plant of Yulin and Wuming. In the tomato Plants of Guiling, Xanthomonas spp., Corynebacterium spp. , Microbacter ium spp. and Erwinia spp. were not found, but Enterobacter spp. , could live in it. There were some different in the endophytic bacteria among varieties.The variety of Hongbaoshi NO. 1 and Meixing were cultivated in Wuming. There was Xanthomonas spp. in the former variety, but later did not be found this bacteria and were found another bacterium-Microbacter ium spp. to live in it. The varieties of Taiwan Shengnu and Hongbaoshi NO.l, which were cultivated in Yulin, were also found different endophytic bacteria between them. Xanthomonas spp. and Corynebacterium spp. could be found in the variety of Taiwan Shengnu. These two bacteria could not be found in the variety of Hongbaoshi NO. 1. But Microbacter ium spp. could live in the variety of Hongbaoshi NO.l. The situation of endophytic bacteria in the variety of Xiahui and Taiwan Shengnu cultivated in Tianyang was the same as that of variety of Taiwan Shengnu and Hongbaoshi NO.l cultivated in Yulin. Xanthomonas spp. and Erwinia spp. were found in Xiahui. These two bacreria did not be found in Taiwanshengnu, but Microbacterium spp and Corynebacterium spp. could live in the variety of Taiwan shengnu.Fourteen of 571 isolates could inhibit the growth of Ralstonia solanacearum ,isolate Bs13 was the strongest inhibition to the pathogen among the 14 isolates. Bs18, Bsl2, Bs35, Bs46, Bm24 andBs13 had both antagonistic activity and promoting the growth of tomato.The isolate of BsI3 was selected to test its biological characteristic. The most suitable temperature for the growth of Bs]3 was from 31 C to 34 ' C. When the temperature increased to 43 C or decreased to 10 ' C, Bs13 stoped growth. The most suitable pH for the growth of Bs13 was from 7-8. When pH increased to 11 or decreased to 5, Bs13 could not grow. Bs13 could use Maltose, Sorbitol, Mannitol, Glucose as carbon sources, it could not use D-Fructose, D-Cellobiose, Dulcitol, Glycerol and Lactose as carbon sources. L-Aspartic acid, DL-Glycine, Methionine, Glycine and NaNO3 were sutable nitrogen source for the growth of Bso, it could not use L-Tyrodsine, L-Glutamic acid, DL-Methionine, L- Methionine and NHtCl as nitrogen source. Basis on the test of morphology and biochemiology, Bso was primarily identified as Agrobacterium radiobacter .