基于可培养方法分析云南腾冲小空山火山谷芽胞杆菌分布特征

Distribution characteristics of Bacillus-like species of Xiaokong Mountain volcanic valley in Tengchong County, Yunnan Province

摘要:

[目的]为了解云南腾冲小空山火山谷土壤中可培养芽胞杆菌种类分布特征。[方法]采用可培养手段对小空山火山谷阳坡、谷底和阴坡土壤中的芽胞杆菌进行分离培养，根据16S rRNA基因序列同源性对分离菌株进行鉴定，并分析系统发育地位。利用Canoco 5软件分析采样点芽胞杆菌种类分布特征与土壤样品理化性质的相关性。[结果]从火山谷土壤样品中共分离获得180株芽胞杆菌，16S rRNA基因测序鉴定结果表明分离菌株隶属于芽胞杆菌纲2个科（芽胞杆菌科和类芽胞杆菌科）、6个属、34个种，其中芽胞杆菌属（Bacillus）11个种，类芽胞杆菌属（Paenibacillus）14个种，短芽胞杆菌属（Brevibacillus）3个种，赖氨酸芽胞杆菌属（Lysinibacillus）4个种，嗜冷芽胞杆菌属（Psychrobacillus）1个种和绿芽胞杆菌属（Viridibacillus）2个种，其中7个菌株与其最近模式菌株16S rRNA相似性低于种的界定阈值（98.65%），为芽胞杆菌潜在新物种。优势属为芽胞杆菌属和类芽胞杆菌属，优势种为蕈状芽胞杆菌（Bacillus mycoides），图瓦永芽胞杆菌（Bacillus toyonensis），蜡状芽胞杆菌（Bacillus cereus），解木糖赖氨酸芽胞杆菌（Lysinibacillus xylanilyticus），蜂房类芽胞杆菌（Paenibacillus alvei）和沙地绿芽胞杆菌（Viridibacillus arenosi）。其中16个种分离自阳坡，29个种分离自阴坡，9个种分离自谷底，三者共同种类为6种。阳坡、谷底和阴坡的芽胞杆菌种群分布Bray-Curtis相似性为62.4%，多样性分析结果表明，Shannon指数（H'）大小次序为阴坡 > 阳坡 > 谷底。环境因子分析发现，芽胞杆菌种群分布多样性特征与其土壤的海拔高度、碳氮比和硫含量呈负相关，而和碳源和氮源含量呈正相关。[结论]从以上结果得出，云南腾冲火山谷有着较为丰富的芽胞杆菌资源，且还存在可分离培养的芽胞杆菌的潜在新物种，为利用火山微生物资源提供了保障。

Abstract:

[Objective] The study was aimed to determine the distribution of Bacillus-like species in volcanic valley of Xiaokong Montain, Tengchong County, Yunnan Province. [Methods] On the basis of culturable method, we isolated Bacillus-like species from soil samples collected in shady-slope, sunny-slope and valley bottom of Xiaokong Mountain. Then the isolates were identified using the 16S rRNA gene and phylogenetic tree was constructed to explore the relation between isolates and related type species. The correlation between environmental factors and community of Bacillus-like species was analyzed by software Cano 5. [Results] We obtained 180 isolates from the soil samples, and identified them as 2 families, 6 genera, 34 species using 16S rRNA gene sequences, including genus Bacillus (11 species), Paenibacillus (13 species), Brevibacillus (3 species), Lysinibacillus (4 species), Psychrobacillus (1 species) and Viridibacillus (2 species). Among them, 7 strains had the lower 16S rRNA similarities with their closest type strain, below the species threshold valus 98.65%, indicating that they were potential novel Bacillus species. The dominant genera were Bacillus and Paenibaciilus, and dominant species were B. mycoides, B. toyonensis, B. cereus, L. xylanilyticus, P. alvei and V. arenosi. Among the Bacillus-like species, we got 16 species from sunny-slope, 29 species from shady-slope and 10 species from valley bottom. The diversity index was showed that the order of Shannon index was shady-slope > sunny-slope > valley bottom. We also found that the correlation between Bacillus-like species community structure, altitude and carbon source was negative, but with S and nitrogen source was positive. [Conclusion] There were rich Bacillus-like species in volcanic valley, Tengchong County, Yunnan Province, and some novel potential Bacillus-like species.