东太平洋中国多金属结核区锰结核样品中微生物群落结构的研究

通过非培养手段研究了东太平洋中国多金属结核区ES0303站点锰结核样品中的微生物群落结构.细菌16S rRNA基因克隆文库的研究结果表明：结核内细菌种群结构复杂,微生物种类丰富且各种群丰度不一（61个OTUs）,其中变形杆菌类群为优势种群,占所有细菌克隆子比例的64%,且主要分布于β/γ-、α-和δ-等3类变形杆菌（Proteobacteria）亚群之中,占比分别为34%、18%和12%.此外还存在包括酸杆菌（Acidobacteria）,放线菌纲（Actinobacteria）,绿弯菌门（Chloroflexi）,厚壁菌门（Firmicutes）,浮霉菌门（Planctomycetes）等在内的细菌类群的分布,克隆子比例依次为9%、7%、8%、2%和5%.古菌16S rRNA基因克隆文库的研究结果表明：古菌的群落结构单一（仅12个OTUs）,全部是由泉古菌海洋类群I（crenarchaeote marine group I,MGI）组成;其中MGI-η类群最为丰富,达到44%,而MGI-α、MGI-ζ和MGI-ε类群的克隆子比例分别为25%、18%和9%,另外还发现2个新的MGI分类类群.相关克隆子的数据库比对和系统发育树分析表明,并未发现已报道的直接参与铁锰氧化还原相关类群的存在,但它们大多数与来自多金属结核来源或深海来源的不可培养微生物具有较高的同源性.进一步的分析表明,锰结核内存在相当数量的氨氧化菌、硫酸盐还原菌、酸杆菌等能够改变pH值的细菌和古菌类群的存在,意味着它们可能在锰结核的形成过程中起到重要的作用.

Study of the microbial community structure of manganese nodule samples from China polymental nodule province in the Eastern Pacific Ocean

The microbial community structure of manganese nodule samples collected from location ES0303 in the China polymetal nodule province of the Eastern Pacific Ocean were studied based on independent-culture methods.The bacterial 16S rRNA gene clone library showed a complex bacterial community structure in these manganese nodules.Bacterial biodiversity was very rich with quite different abundances of each group（61 OTUs）.Among them,Proteobacteria was the dominant group,the proportion of Proteobacteria clones compared to total bacterial clones reached up to 64%,and was mainly distributed in 3 subgroups：β-/γ-（34%）,α-（18%） and δ-Proteobacteria（12%）.Other bacterial groups including Acidobacteria（9%）,Actinobacteria（7%）,Chloroflexi（8%）,Firmicutes（2%） and Planctomycetes（5%） were distributed in the clone library.The archaeal 16S rRNA gene clone library indicated a quite simple archaeal community structure（only 12 OTUs）,totally composed of the Crenarchaeote marine group I（MGI）.Among them,the MGI-η group was the richest,its proportion reaching up to 44% while the proportion of other groups like MGI-α,MGI-ζ and MGI-ε were 25%,18% and 9% respectively.Two novel MGI groups were found in the clone library.Further analysis of these related clones（which were blasted with NCBI database and analyzed from phylogenetic trees） found that these microbes were not related to bacteria well known at sites of iron-manganese oxidation or reduction.Most clones were in fact related with greater homology to uncultured clones originating from polymetal nodules or deep sea environments.Further analysis showed that many bacteria and archaea such as ammonia oxidizing bacteria and archaea,sulfate-reducing bacteria and Acidobacteria which can change the environmental pH value were found in this study.This perhaps suggests an important function for these microbes in the formation of manganese nodules.