吴晓晖 谢永丽 梁欣 张英 芦光新

摘要：通过平板对峙试验以分离筛选自青海托格若格半荒漠沙地、托素湖盐碱地、海北爆轰试验场3个极端生境植被根围的菌株为供试菌株，进行拮抗活性检测；采用16S rDNA及gyrB基因序列分析鉴定菌株；采用CMC法及Gram染色法测定菌株降解纤维素活性；对具降解纤维素活性的拮抗菌株进行促生活性测定。结果表明，菌株TGRG3、TGRG7、TSH5分别对油菜菌核菌（Sclerotinia sclerotiorum）、小麦赤霉菌（Fusarium graminearum）、小麦长孢蠕菌（Helminthosporium tritici-vulgaris）具有拮抗活性，抑菌圈平均直径均>20 mm。3株菌株均被鉴定为枯草芽孢杆菌（Bacillus subtilis），均具降解纤维素及促植物生长活性。

关键词：枯草芽孢杆菌（Bacillus subtilis）；分子鉴定；降解纤维素活性；拮抗活性；促生

中图分类号：Q948.12+2.3 文献标识码：A 文章编号：0439-8114（2018）08-0061-05

DOI：10.14088/j.cnki.issn0439-8114.2018.08.016

Isolation and Identification of Growth-promoting Rhizosphere Strains Isolated from Extreme Environment and Its Biological Activity Analysis

WU Xiao-hui，XIE Yong-li，LIANG Xin，ZHANG Ying，LU Guang-xin

（College of Agricultural and Animal Husbandry，Qinghai University/Key Laboratory of Altiplano Grassland Resource and Ecology，Province and Education Ministry，Xining 810016，China）

Abstract： The strains were isolated from three representative extreme sample area including Tuogeruoge semi-desert sand，Tuosu Lake salt and alkali land，detonation test site of Haibei in Qinghai province. Antagonistic activity detection was used to check antagonistic activity of these strains. Polyphasic molecular taxonomy methods including gyrB and 16S rDNA partial sequence analysis were used to identify these strains. The CMC plate test and Gram staining method were used to analysis cellulose degradation of the bio-control strains. The results showed that three strains including TGRG3，TGRG7 and TSH5 could present distinct antagonistic activity to Sclerotinia sclerotiorum，Fusarium graminearum and Helminthotporium tritici-vulgaris，and diameters of the inhibition zone were all longer than 20 mm. The strains of TGRG3，TGRG7 and TSH5 were identified as Bacillus subtilis. All of three biocontrol B. subtilis strains had cellulose-degradation activity and promotion function on growth of plant.

Key words： Bacillus subtilis； molecular identification； cellulose-degradation activity； antagonistic activity； growth-promoting

芽孢杆菌（Bacillus spp.）革兰氏阳性细菌，好氧或兼性厌氧，能产生耐热、耐盐碱、耐紫外等内源芽孢，环境适应性强，分布于各种环境中，在农牧业、工业和医学研究等方面扮演着极其重要的角色[1]。芽孢杆菌作为根围促生菌（Plant Growth-promoting Rhizobacteria，PGPR），其促生机制包括提高植物根际营养的可利用性，促进难溶性磷、铁和微量元素的吸收；产生植物激素类物质有赤霉素（Gibberellins）、吲哚-3-乙酸（IAA）、细胞分裂素（Cytokinin）等。此外，还可通过抑制病原物、诱导植物抗病性来间接促进植物生长[2]。部分芽孢杆菌能够固氮、溶磷，对土壤有机质进行分解，从而提高土壤肥力，促进土壤营养元素循环；部分芽孢杆菌能产生胞外纤维素酶、半纤维素酶等，能够有效降解木质纤维素[3，4]。芽孢杆菌是当前研究应用较广的一类微生物资源。