Abstract:In order to explore bio-control agents to control tobacco bacterial wilt, Ralstonia solanacearum was chosen as the target pathogen, and one antagonistic bacterial strain X-60 with inhibition zone of around 37 mm was isolated from the soil samples of tobacco rhizosphere in the field. The bacterium was identified as Bacillus amyloliquefaciens according to the morphology, Biolog identification and 16S rDNA analysis. Further antimicrobial spectrum analysis of the B. amyloliquefaciens strain X-60 indicated that the bacterial strain was strongly antagonistic against Botrytis cinerea, Colletotrichum destructivum, Phytophthora parasitica and Alternaria alternata in vitro. The inhibition rates against those pathogens were 51.28%, 58.97%, 60.53% and 72.78%, respectively. Greenhouse test with the bacterial irrigation approach displayed that the B. amyloliquefaciens strain X-60 possessed an excellent protective activity against bacterial wilt in tobacco. The results of phenotype microarrays analysis showed that the antagonistic bacterium could assimilate 41% of the tested carbon substrates, 77% of the tested nitrogen substrates, 86% of the tested phosphorus substrates, 69% of the sulfur substrates, and also presented 91 different biosynthetic pathways. Seventy-two carbon substrates, 45 kinds of nitrogen substrates of amino acids, and around 190 peptone nitrogen substrates could significantly promote the growth of this bacterium. The phosphorus chemicals dithiophosphate and cysteamine-S-phosphate, and the sulfur substrates thiosulfate, S-methyl-L-cysteine and D, L-lipoamide were also efficiently utilized by the B. amyloliquefaciens strain X-60. These findings provide scientific evidence to further develop B. amyloliquefaciens X-60 as a potential bio-control agent and to effectively control tobacco bacterial wilt in the future.