新疆土壤芽胞杆菌采集鉴定及其分布多样性

为了解新疆芽胞杆菌的种类及其多样性情况,将采集于新疆4个地点的14份土样用稀释平板计数法进行芽胞杆菌分离,用MIDI鉴定系统和16SrDNA测序法进行种类鉴定。结果发现,从新疆土样中共分离到53株,13种芽胞杆菌,分别为巨大芽胞杆菌、蜡状芽胞杆菌、枯草芽胞杆菌、嗜碱芽胞杆菌、粘性芽胞杆菌、地衣芽胞杆菌和萎缩芽胞杆菌。通过16SrDNA序列的系统发育树分析发现,分离的菌多数和模式菌株亲缘关系较近,也有少数几株菌与模式菌株亲缘关系较远,可能是由于芽胞杆菌属中各个种之间具有较近的亲缘关系,在种的系统发育上也存在一定的交叉,各菌株间序列差异较小。根据土壤中芽胞杆菌多样性研究发现,不同土壤标本内的芽胞杆菌含量差异显著表现为阿拉尔市>新疆喀什>阿克苏>塔克拉玛干沙漠。而每个地点中同种芽胞杆菌的含量差异也较显著,如:蜡样芽胞杆菌在阿克苏的含量为5.230×105 cfu.g-1,而在塔克拉玛干沙漠的含量仅仅为0.7×103cfu.g-1。新疆芽胞杆菌较丰富,不同地点芽胞杆菌在种类和数量上都有很大差异,每个地点都含有独特的芽胞杆菌。

Collection,Identification and Phylogenetic Diversity of Bacillus species in Soil Samples from Xinjiang

The present study dealt with the collection,identification and phylogenetic diversity of Bacillus species in soil samples from Xinjiang.Fourteen soil samples were used for the microbial identification based on their fatty acid compositions and 16S rDNA sequences.As a result,53 strains were isolated and identified as 13 species including B.megaterium,B.cereus,B.subtilis,B.alcalophilus,B.viscosus,B.licheniformis,B.atrophaeus,etc.The phylogenetic tree analysis clustered their 16S rDNA sequences for genetic relationship among them.Based on the diversity indices,the Bacillus counts in soils from different locations were found to vary significantly.For instance,the number in Alaer was greater than those in Xinjiang Kashen,Akesu and Takelamagan,in that order.Even the same species in the soil from a same locality could differ significantly.For example,Bacillus cereus was 5.230×105 cfu·g-1 in Akesu,but only 0.7×103 cfu·g-1 in Takelamagan.Bacillus existed abundantly in Xinjiang,and the varieties and quantities in the soils also varied greatly.