一株分离自胡杨的赖氨酸芽孢杆菌(Lysinibacillus)ML-64的微生物学特性

Microbiological characteristics of a Lysinibacillus strain isolated from Populous euphratica

摘要:

摘要:【目的】从胡杨茎秆液中分离得到的一株菌株ML-64，对其进行微生物学特性的分析。【方法】通过细菌培养和染色的方法进行了形态和培养特征的检测，使用多相分类学方法测定菌株的各项生理生化指标，脂肪酸组分、醌组分、极性脂类型、16S rRNA基因系统发育分析、(G+C)mol%含量的测定和DNA-DNA杂交分析。【结果】菌株ML-64为革兰氏阳性菌，杆状，产生芽孢。菌落为圆形，淡黄色，表面光滑。菌株生长温度范围为10－45℃(最适37℃)，pH范围为7.0－9.0(最适pH7.0)，NaCl浓度范围为0－6%(W/V) (最适0－2%)。菌株ML-64 的类脂酯酶，精氨酸双水解酶，脲酶活性和VP-实验为阳性。在API 50CH酶活性检测实验中菌株不能发酵任何糖类。可利用的碳源有: L-丝氨酸，丙酮酸甲酯，α-酮-丁酸，乙酰乙酸。对多粘菌素B(30 μg)、新生霉素(30 μg)、青霉素G(10 U)不敏感。16S rRNA基因序列分析结果表明，菌株ML-64T与ysinibacillus chungkukjangi 2RL3-2T，Lysinibacillus sinduriensis BLB-1T有密切亲缘关系。相似率分别为100%和99.1%。菌株ML-64与Lysinibacillus chungkukjangi 2RL3-2T和Lysinibacillus massiliensis CIP108446T之间的杂交率分别为82%和50.9%。基因组DNA(G+C)mol%含量为36.8%。菌株ML-64优势脂肪酸类型为iso-C15:0(55.05%)和anteiso-C15:0(20.70%)，醌组分类型是MK-7。【结论】基于表型特征、遗传型特征和系统发育分析，将菌株定为Lysinibacillus chungkukjangi的新变种，获得序列注册号为KC609752。胡杨内生菌ML-64的基因组结构已与最近源菌株L．chungkukjangi产生了较大的分化，选择性地适应了胡杨内生环境。

关键词:关键词:赖氨酸芽孢杆菌属，胡杨内生细菌，多相分类学鉴定

Abstract:

Abstract:［Objective］The aim of this study was to identify the microbiological characteristics of a Lysinibacillus strain isolated from storage liquid in the stems of Populus euphratica trees． ［Methods］ Bacterial morphology and cultivation characteristics were studied by conventional cultivation and dyeing method． Biochemical characteristics，fatty acid components，menaquinone，polar lipids，phylogenetic analyses of 16S rＲNA，determination of (G+C) mol% content and DNA- DNA hybridization were studied by polyphasic taxonomic approach．［Results］Strain ML-64 is Gram-positive，endospore-forming and rod-shaped． Colonies are pale-yellow，circular and entire margin．Temperature range for growth is between 10 and 45 ℃ (optimum at 37 ℃)．The pH range for growth is between 6. 0 and 9.0 (optimum at 7.0)．NaCl concentration range for growth is between 0 and 6% (optimum 3%)．Cells were positive for lipid esterase，Arginine dihydrolase，urease and Voges-Proskauer test． No sugars were fermented in the API 50CH strips．L-Serine，Methyl Pyruvate，α-Keto-Butyric，Acetoacetic Acid were oxidized．Resistant to polymyxin b (30 μg)，novobiocin (30 μg)，peillin G (10 U)．16S rRNA gene sequence demonstrated that strain ML-64 was closely related to Lysinibacillus chungkukjangi 2RL3-2T (100%)，Lysinibacillus sinduriensis BLB-1T (99.1%)．DNA-DNA relatedness were 82% and 50.9% with Lysinibacillus chungkukjangi 2RL3-2T and Lysinibacillus massiliensis CIP108446T，respectively． The genomic DNA G+C content of strain ML-64 was 36.8% (mol)． Major fatty acids were iso-C15:0 ( 55.05% ) and anteiso-C15:0 (20.70%)．The predominant menaquinone is MK-7．Based on the phenotypic phylogenetic and genotypic analyses，the strain ML-64 is concluded to represent a new mutant strain of the Lysinibacillus chungkukjangi species，GenBank accession number is KC609752．［Conclusion］As an endophytic bacterium of Populus euphratica，genomic structure of the strain ML-64 was greatly differentiated from the closest strain L． chungkukjangi，and suitably adapted to the endophytic environment of Populus euphratica．

Key words:Keywords: genus Lysinibacillus，endophytic bacterium of Populus euphratica，polyphasic taxonomic approach