摘 要 ：利用非培养的分子技术研究了西沙海槽表层沉积物中的微生物群落。沉积物中扩增的古菌16S rDNA 序列分属两个大类：泉古生菌(Crenarchaeota)和广古生菌(Euryarchaeota)。以Marine Crenarchaeotic GroupⅠ (古菌16S rDNA文库的49.2%)和Terrestrial Miscellaneous Euryarchaeotal Group (16.9%)为主要类群；其余为Marine Benthic Group B (9.7%)、 Marine Benthic Group A (4%)、 Marine Benthic Group D (1.6%)、Novel Euryarchaeotic Group (0.8%)和 C3(0.8%)。细菌克隆子多样性明显高于古菌，16S rDNA序列分别来自变形杆菌(Proteobacteria)(细菌16S rDNA文库的30.5%)、浮霉菌(Planctomycetes)(203%)、放线菌(Actinobacteria)(14.4%)、厚壁菌(Firmicutes)(15.3%)、屈桡杆菌(Chloroflexi)(8.5%)、酸杆菌(Acidobacteria)(34%)、candidate division OP8 (2.5%)、拟杆菌/绿菌(Bacterioidetes/Chlorobi)(1.7%)和疣微菌(Verrucomicrobia)(17%)。变形杆菌为优势类群(包括Alpha-和Delta-Proteobacteria亚群)。多数克隆子为未培养细菌和古菌。结果表明南海表层沉积物中蕴含大量未知的微生物资源。
Abstract:Microbial communities were obtained from surface sediments of the Xisha Trough using cultured-independent technique. The characterization of the 16S rDNA gene amplified from the sediments indicated that archaeal clones could be grouped into the Euryarchaeota and Crenarchaeota domains respectively. Two archaeal assemblages, the Marine Crenarchaeotic GroupⅠ (49.2% of the total archaeal clones) and the Terrestrial Miscellaneous Euryarchaeotal Group (16.9%), were the most dominant archaeal 16S rDNA gene components in sediments. The remaining sequences were related to members of the Marine Benthic Group B (9.7%), Marine Benthic Group A (4%), Marine Benthic Group D (1.6%), Novel Euryarchaeotic Group (0.8%) and C3 (0.8%). The bacteria clones exhibited greater diversity than the archaeal clones, with the 16S rDNA gene sequences from members of the Proteobacteria (30.5% of the total bacterial clones), Planctomycetes (20.3%), Actinobacteria (14.4%), Firmicutes (15.3%), Chloroflexi (8.5%), Acidobacteria (34%), candidate division OP8 (2.5%), Bacterioidetes/Chlorobi (1.7%) and Verrucomicrobia (1.7%). Most of these lineages represented uncultured and undescribed groups of bacteria and archaea. The results suggest that a vast amount of microbial resource in the surface sediment of the South China Sea is yet to know.