1株广谱抗真菌芽孢杆菌TR21的鉴定

利用API50CH鉴定系统、16S rDNA、gyrA和gyrB基因序列分析法,对1株分离自石斛兰叶片的广谱抗真菌芽孢杆菌TR21进行生化和分子鉴定。通过API50CH系统测试,TR21菌株与枯草芽孢杆菌相似性为90.3%,被鉴定为枯草芽孢杆菌。利用16SrDNA序列分析发现TR21菌株与枯草芽孢杆菌(Bacillus subtilis)、B.subtilis subsp.subtilis、B.subtilis subsp.spizizenii和B.velezensis的相应核苷酸序列具有很高的同源性,其序列相似性皆为99%,而基于gyrA和gyrB基因序列构建的系统发育树显示,该菌株与枯草芽孢杆菌的相似性分别为96%和91%。结合16SrDNA、gyrA和gyrB基因序列分析,也确定该菌为枯草芽孢杆菌。比较API鉴定和基于不同基因的鉴定发现,分子鉴定更加快速、灵敏。

Identification of a Bacillus Strain TR21 with Broad-range Antifungal Activity

API 50 CH identification system, 16S rDNA, gyrA and gyrB gene sequence analysis were used to identify Bacillus strain TR21, which exhibited broad-range antifungal activity and was isolated from the leaves of Dendrobium Archid. Based on the API 50 CH system tests, the strain TR21 was of similarity of 90.3% with B. subtilis. Based on 16S rDNA sequence homology, the strain TR21 was 99% similar with Bacillus subtilis, B. subtilis subsp. subtilis, B. subtilis subsp. spizizenii and B. velezensis in corresponding nucleotide sequences. But based on Blast results with gyrA gene sequence or gyrB gene sequence, phylogenetic trees showed TR21 shared 96% or 91% identity with B. subtilis, respectively. Combined with 16S rDNA, gyrA and gyrB gene sequence analysis, the strain TR21 was confirmed as B. subtilis. Molecular identification was more sensitive and rapid than API identification system.