南极中山站长城站土壤及海洋沉积物可培养细菌多样性

Diversity of culturable bacteria in soils from Zhongshan and Changcheng stations and marine sediments from Antarctica

南极地区具有气候酷寒干燥、强紫外(UV)辐射和季节性光照与温度波动等恶劣的极端环境条件,孕育了大量微生物资源和潜在新物种。为了挖掘南极不同生境样品蕴含的微生物菌种资源,更好地认识和探索南极地区微生物资源多样性,利用低温寡营养富集结合梯度稀释涂布的方法,对南极长城站、中山站土壤和近海表层沉积物3个生境的样品进行细菌分离和16S rRNA基因序列相似性分析以确定南极细菌分类学地位。结果表明,共获得482株纯培养细菌,有54个属,142个种,分布于变形菌门(Proteobacteria,42%),放线菌门(Actinobacteria,40%),厚壁菌门(Firmicutes,12%),拟杆菌门(Bacteroidetes,4%)和异常球菌-栖热菌门(Deinococcus-Thermus,1%)。优势属为嗜冷杆菌属(Psychrobacter,12%)、假单胞属(Pseudomonas,10%)和节杆菌属(Arthrobacter,9%)。不同生境样品中纯培养细菌多样性存在较大差异。中山站干燥土壤样品中放线菌门比例明显高于变形菌门,有13个特有属,嗜冷杆菌属(Psychrobacter)、红球菌属(Rhodococcus)为优势菌;长城站近岸砂土样品中变形菌门菌株最多,拟杆菌门比例高于中山站样品,有高比例的假单胞菌,分离到12个特有属;近海沉积物样品细菌群落结构最简单,分离到9个特有属。经16S rRNA基因序列对比发现,有7株菌为潜在新种。

Antarctic region has severe extreme environmental conditions such as cold and dry climate,strong UV radiation and seasonal light and temperature fluctuation,and breeds a large number of microbial resources and potential new species.Method of low-temperature-oligotrophic-enrichment combined with gradient dilution was performed to isolate bacteria in soils from Zhongshan and Changcheng stations and marine sediments from Antarctica for the purpose to explore microbial resources in different habitats and to better understand the culturable bacteria diversity in the region.A total of 482 bacterial strains were obtained and belonged to 54 genera and 142 species after 16 S rRNA gene sequencing.The strains were mainly grouped into 5 phyla:Proteobacteria(42%),Actinobacteria(40%),Firmicutes(12%),Bacteroidetes(4%)and Deinococcus-Thermus(1%).The dominant genera were Psychrobacter(12%),Pseudomonas(10%)and Arthrobacter(9%).Diversity of culturable bacteria in different soil samples was different.The proportion of Actinobacteria in the dry soil samples from Zhongshan station was significantly higher than Proteobacteria.There were 13 endemic genera,with Psychrobacter and Rhodococcus as the dominant genera.Proteobacteria dominated in soils from Changcheng station area and the proportion of Bacteroidetes was higher than that of the samples from Zhongshan station.Pseudomonas was the dominant genus and 12 endemic genera were isolated.The bacterial community structure of the sediment samples was the simplest and 9 endemic genera were isolated.It was suggested that 7 isolates could be potential novel species by their low 16 S rRNA gene sequence similarity.