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为探讨烟草根际生防细菌的生防机制,从重庆地区连作烟田健康烟株根际土壤中分离筛选到1株对烟草疫霉具有较强拮抗作用和对黑胫病具有良好防效的细菌菌株P-72-10。根据培养性状、形态特征、生理生化特性、基因组DNA的(G+C)mol%含量测定以及16S rDNA基因序列分析确定该菌株的分类地位。该菌株菌落乳白色,能产生水溶性荧光色素,革兰氏染色反应阴性,菌体杆状、大小(8.1～16.2)μm×(1.8～4.8)μm,单端生鞭毛,不形成芽孢。The BIOLOG GN2结果显示该菌株属于假单胞菌属Pseudomonas。该菌株基因组DNA的(G+C)mol%含量为60.72 mol%。16S rDNA基因序列分析显示该菌株与假单胞菌属荧光假单胞杆菌多个菌株的序列同源性达到99%,GenBank上的登录号为:HQ888871。结合其形态特征和生理生化特性,将菌株P-72-10鉴定为荧光假单胞杆菌P.fluorescens。平板检测拮抗代谢产物结果表明:该菌株具有分解纤维素、蛋白质和结合Fe3+的能力,但不能分解几丁质。
In order to explore the biocontrol mechanism of biocontrol bacteria in the rhizosphere of tobacco, one strain that has strong antagonism against Phytophthora nicotianae and a good anti-black-shank disease was isolated and screened from rhizosphere soils of healthy tobacco plants in continuous cropping tobacco fields in Chongqing. Bacterial strain P-72-10. The taxonomic status of this strain was determined according to the traits, morphological characteristics, physiological and biochemical characteristics, (G + C) mol% content of genomic DNA and 16S rDNA gene sequence analysis. The strain colony milky white, can produce water-soluble fluorescent pigment, Gram staining negative, the rod-shaped cells, size (8.1 ~ 16.2) μm × (1.8 ~ 4.8) μm, single- The BIOLOG GN2 results show that the strain belongs to Pseudomonas. The (G + C) mol% content of the strain genomic DNA was 60.72 mol%. The 16S rDNA gene sequence analysis showed that the sequence homology between Pseudomonas fluorescens and Pseudomonas fluorescens was 99%. The accession number in GenBank was HQ888871. According to its morphological and physiological and biochemical characteristics, strain P-72-10 was identified as P.fluorescens. Antagonistic metabolites showed that the strain has the ability of decomposing cellulose, protein and binding Fe3 +, but can not decompose chitin.