武夷山自然保护区土壤可培养芽胞杆菌的物种多样性及分布

Diversity and distribution of cultivable Bacillus-like species in soils collected from Wuyishan Nature Reserve

为了解武夷山自然保护区土壤中可培养芽胞杆菌的分布状况，2012年6月从该保护区的黄岗山顶部、中部、底部和桐木关、挂墩、大竹岚等6个地点采集土样75份。用80℃水浴加热、稀释平板法进行芽胞杆菌的分离，并根据16SrRNA基因序列分析对菌株进行初步鉴定。从土样中分离出芽胞杆菌418株，鉴定为8个属42个种，其中Bacillus属的种数最多，有20种，Paenibacillus属和Lysinibacillus属分别有8种和7种。不同地点分离到的芽胞杆菌在种类、数量上存在差异：从大竹岚土壤中分离到的芽胞杆菌种类最多，从黄岗山中部和底部分离到的种类数则较少；挂墩、大竹岚土壤中芽胞杆菌的数量较大，达3．6×10^6cfu／g以上，而黄岗山顶部和中部土壤中的数量则少于4．9×10^5cfu／g。Bacilluscereus、B．mycoides、B．thuringiensis和Lysinibacillusxylanilyticus等4个种在6个地点的土样中均有分离到，其中B．thuringiensis、L．xylanilyticus是该保护区土壤中的优势种。桐木关土壤中芽胞杆菌的种类多样性和均匀度指数都比其他5个地点的高，而挂墩土壤中芽胞杆菌的Shannon-Wiener多样性、均匀度和优势度指数都最低。B．mycoides和B．thuringiensis的数量与海拔显著相关，相关系数分别为0．85231-0．834，B．cereus、B．mycoides、B．thuringiensis的分离频度与海拔的相关性极显著，相关系数分别为0．960、0．952和-0．931。研究结果表明，武夷山自然保护区土壤中可培养芽胞杆菌的种类丰富、数量较大，具有较高的多样性。

The present paper reported the distribution and diversity of cultivable Bacillus-like species in soils from Wuyishan National Nature Reserve. In June 2012, 75 soil samples were collected from the peak, middle and base of the Huanggang Mountain, Tongmuguan, Guadun, and Dazhulan in the reserve. The Bacillus-like species were isolated by plating the series dilution after 80 ℃ water bath heating the soil samples and then identified using 16S rRNA gene sequence analysis. Results showed that 418 strains isolated from the soil samples belonged to 42 Bacillus-like species, which were grouped into eight genera containing Bacillus, Brevibacillus, Fictibacillus, Lysinibacillus, Paenibacillus, Psychrobacillu, Rummeliibacillus and Viridibacil- lus. Furthermore, Bacillus was the dominant genus, followed by the genera Paenibacillus and Lysinibacillus. The greatest number of Bacillus-like species was isolated from the soils in Dazhulan, while the fewest were found at the middle and base of Huanggang Mountain. The quantities of Bacillus-like species in soils col- lected from Guadun and Dazhulan were more than 3.6× 10^6 cfu/g soil, but less than 4.9× 10^5 cfu/g soil at the top and middle of Huanggang Mountain. Bacillus cereus, B. mycoides, B. thuringiensis, and Lysinibacillus xylanilyticus were isolated from all six sites, which were dominated by B. thuringiensis and L. xylanilyticus. The Shannon-Wiener diversity index and Pielou＇s evenness index for Bacillus-like species isolated fromTongmuguan were higher than those at the other five sites, while the lowest Shannon-Wiener diversity index, Pielou＇s evenness index and Simpson index values were found in the soils from Guadun. There was a sig- nificant correlation between the altitude and the quantity of B. mycoides and B. thuringiensis, with correla- tions of 0.852 and -0.834, respectively. Additionally, highly significant correlations were found between the altitude and the isolating frequency orB. cereus, B. mycoides and B. thuringiensis, with correlations of 0.960, 0.952 and -0.931, respectively. These results indicated the abundance and diversity of the Bacillus-like spe- cies community and bacteria species were extremely rich in Wuyishan Nature Reserve.