西北太平洋深海底栖有孔虫DNA分子多样性与群落组成特点的初步研究

深海蕴藏着丰富的自然资源,是目前世界各国争相探索的战略要地。本工作以底栖有孔虫为研究对象,研究了它在西北太平洋深海（水深4080 m至5830 m）的DNA分子多样性和群落组成特点。我们共采集了11个站位的表层沉积物,提取了样品中的总基因组DNA,利用有孔虫特异性引物扩增了其中的有孔虫DNA,应用高通量测序技术对获得的有孔虫DNA片段测序。最终,共获得1536个操作分类单元（operational taxonomic units,简称OTUs）,有1330个OTUs成功注释到有孔虫,其中721个（约54%）有孔虫OTUs属于起源最早但研究较少的软壳类单房室有孔虫。有孔虫OTUs注释结果的Identity值的平均值为92.9%,Identity值大于或等于97%的OTUs仅占20.6%,Identity值小于95%的OTUs占63.1%,说明西北太平洋深海底栖有孔虫与目前检获到的有孔虫之间存在较明显的遗传差异性,该海区极可能蕴藏着大量至今未被发现的"新物种"甚至新的高级分类阶元。在我们获得的有孔虫属中,有1/ 3呈典型的斑块性分布,且站位间的有孔虫群落结构也存在明显差异。本工作是国内利用高通量测序技术对西北太平洋深海底栖有孔虫开展调查的首次尝试,旨在为探索有孔虫的全球地理分布模式、开发和利用深海资源等工作提供分子生态和分子遗传数据支持。

A preliminary study on the DNA molecular diversity and community composition of deep-sea benthic foraminifera from the northwest Pacific Ocean

The deep sea has become a strategic area for countries around the world to develop natural resources,but the diversity and distribution of abyssal organisms are still poorly known.By using high-throughput sequencing technology,we evaluated the molecular diversity of benthic foraminifera,a major component of abyssal communities and a useful proxy in paleoceanography,in the northwest Pacific Ocean(32.2°~36.0°N,145.5°~156.5°E).We collected eleven sediment samples from the northwest Pacific Ocean with water depths between 4080 and 5830 m and extracted the total genomic DNA from each sample.Foraminiferal DNA fragments were amplified with foraminiferal-specific primers and were sequenced by high-throughput sequencing technology.Finally,we obtained a total of 1536 operational taxonomic units(OTUs).1330 OTUs were successfully assigned to Foraminifera,of which 721 OTUs(about 54%)were placed to early(ancient)lineages of soft-walled,single-chambered(monothalamous)foraminifera.The mean identity value of all detected foraminiferal OTUs was 92.9%.Only 20.6%of OTUs had an identity value greater than or equal to 97%and 63.1%of OTUs had an identity value less than 95%.This indicated that the benthic foraminifera in our survey regions had great genetic divergence with those species obtained in previous studies and the northwest Pacific Ocean might contain a large number of"new species"or even high-level taxonomic groups.A third of foraminiferal genera obtained in our study had spatial heterogeneity,and the foraminiferal community structure in different sites showed obvious variation.This work is the first attempt to investigate deep-sea benthic foraminifera in the northwest Pacific Ocean using high-throughput sequencing technology in China and aims to provide bioecological and genetic data for studying the global geographic distribution of foraminifera and exploring deep-sea resources.