Abstract: In this paper, the isolation and identification of endophytic bacteria from Taxus wallichiana var. mairei, screening of IAA producing strain and the production of lipopeptides by IAA producing strain were studied. Using tissue grinding method, the endophytic bacteria was isolated from fresh tissues of T. wallichiana var. mairei. Using 16S rRNA sequencing technology, the isolated endophytic bacteria was identified and analyzed. The IAA content in the extract was determined by high performance liquid chromatography-high resolution flight mass spectrometry and the lipopeptide compounds in the extract were separated and identified by high performance liquid chromatography-TOFMS. Variation of lipopeptide-producing compounds and their contents were screened in screening strains based on database. Results showed that thirty-one endophytic bacteria were isolated and identified from the rhizomes, stems and leaves of T. wallichiana var. mairei. And twenty IAA-producing strains were screened out. Among them, Bacillus strain KLBMPTC10 produced IAA as high as 210.3955 μg·L^-1. In the study of lipopeptide production by IAA-producing strains, it was found that KLBMPTC10 was the most abundant lipopeptide in all IAA-producing endophytic bacteria, and its relative content of Iturin A2 was 26.06%, which was obviously superior to other IAA-producing strains. Bacillus strain KLBMPTC10 had the high ability to produce IAA and lipopeptides at the same time. It may be used as a research strain for further development and research.

Key words: Taxus wallichiana var. mairei, IAA-producing strains, bacillus strain, endophytic bacteria, lipopeptides

摘要： 通过组织研磨法对南方红豆杉(Taxus wallichiana var. mairei)新鲜组织进行内生细菌的分离，利用16S rRNA测序技术对分离的内生细菌进行鉴定分析，使用高效液相色谱-高分辨飞行质谱测定菌液提取物IAA含量，利用HPLC-TOF-MS对提取物脂肽类化合物进行分离、鉴定，结合数据库筛选菌株产脂肽类化合物种类及含量差异。结果表明，从南方红豆杉根茎叶中共分离鉴定出内生细菌31株，筛选出产IAA菌株20株，其中编号为KLBMPTC10的芽胞杆菌属菌株产IAA含量高达210.3955 μg·L^-1。在对产IAA菌株所产脂肽类化合物的研究中发现，菌株KLBMPTC10是所有产IAA内生细菌中脂肽类化合物含量最丰富的，其产Iturin A2相对含量为26.06%，明显优于其他产IAA菌株。芽胞杆菌属菌株KLBMPTC10同时具备高产IAA和脂肽类化合物的能力，可作为研究菌株进一步开发。

关键词: 南方红豆杉, 产IAA菌株, 芽胞杆菌, 内生菌, 脂肽类化合物