非培养手段分析珠江口淇澳岛海岸带沉积物中的古菌多样性

Vertical distribution and diversity of Archaea in coastal sediments of Qi'ao Island(Zhujiang River Estuary),southern China,estimated by 16S rDNA analysis

利用古菌16SrDNA特异引物对珠江口淇澳岛海岸带沉积物中古菌的多样性及垂直分布特征进行研究。结果表明珠江口淇澳岛海岸带沉积物中古菌多样性丰富,大部分为新的不可培养古菌;泉古菌在整个沉积物柱中是优势菌群,约占81%;古菌多样性随沉积物深度增加而增加,区系结构也随深度变化而呈现出明显的不同,在表层沉积物中,88%的序列属于Ⅰ型海洋泉古菌(MGⅠ),而在中层和底层检测到的古菌序列大部分与不可培养的富含甲烷的环境序列有最高的同源性,并且有15%的克隆子序列属于甲烷八叠球菌目(Methanosarcinales)和甲烷微菌目(Methanomicrobiales)。QC-PCR结果表明珠江口淇澳岛海岸带沉积物中古菌含量丰富[(1.93±0.60)×106^(6.45±0.25)×10716S rDNA拷贝/g],呈现随深度增加含量增加的趋势。

The vertical distribution and diversity of archaea in the profile of sediment from Qi＇ao Island （Zhujiang River Estuary） were investigated by molecular phylogenetic methods. Sequence analysis showed that the archaeal diversity was high in estuarine sediments and many archaea were some new, uncultured archaea. The Crenarchaota （81%） were predominated along the sediment core. The community structure and diversity of archaea shifted greatly within vertical distance. 88 % archaeal sequences from the surface layer fell into marine nitrification Creanarchaeon; most of archaeal sequences from the middle and bottom layers were closely related to environmental clones from methane-rich environments and 15% archaeal sequences in the middle layer clustered with Methanosarcinales and Methanomicrobiales. In addition, the results of QC-PCR demonstrated that the abundance of archaea was high[（1.93 ± 0. 60） × 10^6～ （6.45 ±0.25） × 10^7 16S rDNA copies/g] and increased when the depth increased.