青海湖与中国内陆盐湖古菌群落组成的比较

Comparison of archaeal community composition between Qinghai Lake and other salt lakes in China

摘要:

[目的]本研究旨在全面揭示中国最大的内陆咸水湖——青海湖的古菌群落结构，并对青海湖与盐湖的古菌多样性及群落结构进行比较。[方法]随机选取了青海省的茶卡盐湖、陕西省的花马池盐湖和苟池盐湖以及山西省的运城盐湖作为盐湖组。青海湖与盐湖组每个湖泊各采取5个样品，采用针对16S rRNA基因的高通量测序技术分析5个湖泊中的古菌群落组成。[结果]研究发现，青海湖的优势菌群为DHVEG-6_norank、Methanomicrobia_unclassified、Methanobacterium（甲烷细菌属）、Methanolobus（甲烷叶菌属）、Candidatus_Methanomethylophilus、Miscellaneous_Euryarchaeotic_Group（MEG）_norank、AMOS1A-4113-D04_norank、Methanosarcina（甲烷八叠球菌属）、Miscellaneous_Crenarchaeotic_Group_norank。其中，DHVEG-6_norank（70.46%）占绝对优势，但该类群在盐湖中含量极少。4个盐湖的共有优势属为Halonotius、Halorubrum（盐红菌属）、Natronomonas（嗜盐碱单孢菌属）、Halobellus和Haloarcula（盐盒菌属）。对于青海湖与盐湖之间的古菌群落多样性，影响最大的因素为湖水的矿化度，矿化度与5个湖泊的古菌多样性呈负相关，矿化度较低的青海湖群落组成与其他4个盐湖差异显著，无共同优势菌；其次为pH，pH与湖泊中古菌群落多样性呈微弱正相关，小幅度影响到某些菌属的丰度；而本文研究范围内的海拔与其群落结构及多样性没有明显相关性。[结论]青海湖与其他4个盐湖之间的群落结构及多样性有显著差异，矿化度对古菌群落多样性具有显著影响。另，本次测序发现5个湖泊中均有大量未分类的古菌，应为潜在的新种。

Abstract:

[Objective] We compared the difference of community structure of archaea between Qinghai Lake (the largest inland saltwater lake in China) and several other salt lakes in China.[Methods] Chaka Salt Lake in Qinghai Province, Huamachi Salt Lake and Gouchi Salt Lake in Shaanxi Province, and Yuncheng Salt Lake in Shanxi Province were randomly selected as the sample pool. From each lake five samples were taken and analyzed with the high-throughput sequencing technology for 16S rRNA gene.[Results] The dominant genera of Qinghai Lake were DHVEG-6_norank, Methanomicrobia_unclassified, Methanobacterium, Methanolobus, Candidatus_Methanomethylophilus, Miscellaneous_Euryarchaeotic_Group(MEG)_norank, AMOS1A-4113-D04_norank, Methanosarcina, Miscellaneous_Crenarchaeotic_Group_norank. Among them DHVEG-6_norank (70.46%) was absolutely dominant whereas it was hardly found in other salt lakes. On the contrary, the dominant genera in the other 4 salt lakes are Halonotius, Halorubrum, Natronomonas, Halobellus and Haloarcula. Degree of mineralization was the most influential factor that affected the structure of the archaea communities in Qinghai Lake and other salt lakes. The community structure of Qinghai Lake with a low degree of mineralization was significantly different from that of the other 4 salt lakes. The second factor is pH that affected the abundance of some species. However, no significant correlation between the altitude and the community structure was found.[Conclusion] The community structure and diversity of Qinghai Lake was significantly different from that of other 4 salt lakes and it was mainly influenced by the degree of mineralization.