青岛海域固氮细菌的系统发育多样性研究

采用严格人工无氮海水培养基富集、分离培养方法及用3对固氮基因(nifH)引物进行PCR检测,从青岛近海沉积物和海水中分离到16株异养型可培养海洋固氮细菌,经16S rDNA全序列测定分析了它们的系统发育多样性。结果显示,16株菌分布于Alphaproteobacteria、Gammaproteobacteria、Flavobacteria的3个纲中,分别代表着6个属、10个种,其中有50%归于Pseudoalteromonas属;海底沉积物中固氮菌的多样性要远高于海水,并在其中发现2个潜在新种。研究表明,青岛近海海域的固氮菌具有一定程度的多样性,它们大部分在系统发育关系上与分离自韩国、南极洲、新喀里多尼岛等海水的标准菌高度同源,但也存在少量潜在新物种。结果可为其他不同海域异养固氮菌的多样性及其生态功能研究提供有益参考。

Phylogenitic Diversity of Nitrogen-fixing BacteriaIsolated from Qingdao Sea

16 Heterotrophic nitrogen-fixing bacteria were isolated from Qingdao sea using strict artificial nitrogen free medium and detected by nifH-PCR. The phylogenitic diversity of these nitrogen-fixing bacteria were examined based on 16S rRNA gene sequence analysis. The result shown that these bacterial population belonged to 3 classes, 6 genera and 10 species, and 50% of it belong to Pseudoalteromonas. The bacteria diversity of seafloor sediments were far higher than that of sea water, and two potential new species were found in it. This study shows that the nitrogen-fixing bacteria in Qingdao sea has a certain degree of phylogenitic diversity. Most of it has a Highly homologous on the phylogenetic relationship with those standard strains isolated from the sea water of South Korea, Antarctica, New Caledonia island, and et.al, but a few of potential new species also be found. This result can provide a useful reference for expanding study on the species diversity of ocean heterotrophism nitrogen-fixing bacteria and its functions in different marine ecology.