烟草青枯病拮抗菌株X-60的分离鉴定及其表型组学分析

Isolation,identification and phenotype microarrays analysis of an antagonistic bacterial strain X-60 against tobacco bacterial wilt

为了探寻烟草青枯病的生防菌剂,本研究以烟草青枯病菌为指示菌,从烟草根围土壤中分离获得拮抗细菌X-60,其抑菌圈大小约为37 mm。经形态观察、Biolog鉴定及16SrDNA序列分析,该细菌为解淀粉芽孢杆菌。抗菌谱测定表明,它对烟草灰霉病菌、烟草炭疽病菌、烟草黑胫病菌和烟草赤星病菌均具有较强的拮抗作用,菌丝生长抑制率分别为51.28%、58.97%、60.53%和72.78%。温室盆栽试验表明,X-60菌液灌根对烟草青枯病发生具有良好的预防作用。表型芯片研究结果表明,解淀粉芽孢杆菌能代谢41%的碳源、77%的氮源、86%的磷源、69%的硫源,具有91种生物合成途径;72种碳源、45种氨基酸类氮源和190余种肽类氮源均能显著促进该菌的生长;其高效代谢的磷源有二硫代磷酸盐和半胱胺S-磷酸盐,高效代谢的硫源有硫代硫酸盐、S-甲基-L-半胱氨酸和硫辛酰胺。研究结果为解淀粉芽孢杆菌X-60生防菌剂的开发及将其应用于烟草青枯病的生物防治提供了理论基础。

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 16 S 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 presented91 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.