Protistology 9 (2) 88–98 (2015) |
Microbial genetic diversity in soils along saline-alkaline gradients at the coast of Laizhou Bay |
Institute of Oceanology, Chinese Academy of Sciences, 266071 Qingdao, China Summary The soils along the coast of Laizhou Bay in China have suffered serious salinization due to natural reasons and anthropogenic effects, and thus represent a salt-affected environment. Using denaturing gradient gel electrophoresis (DGGE) and gene sequencing, we investigated the genetic diversity of microorganisms in relation to environments, in particular soil salinity (0.1-19 psu) and pH (7.9-10) at five sites in the coastal soils of the Changyi National Marine Specific Protection Area and an adjacent idle salt field. There were obvious shifts of both the microeukaryotic and prokaryotic communities along the environmental gradients. The sequencing of microeukaryotic bands uncovered highly diverse groups which were primarily dominated by Cercozoa. The sequences of Cercomonadida were detected for the first time from highly saline soils (about 19 psu), while the upper limit of Cercomonadida in saline soil and aquatic environments detected by previous studies was 5 psu. The sequencing of bacterial bands revealed the presence of Proteobacteria at all sites, whereas Acidobacteria were only detected at sites with low salinity and high pH. Cluster analysis of both microeukaryotic and prokaryotic DGGE profiles classified the five sites into three main groups, which was consistent with the analysis based on both the environmental factors and the abundance of diatoms, ciliates, testate amoebae and nematodes. Statistical analyses indicated that soil salinity was the primary factor in regulating the microbial genetic diversity, while the combination of pH and phosphorous content was the most important factor in explaining the changes of microeukaryotic and prokaryotic communities along the environmental gradients in the coastal soils.
Key words: Cercozoa, coastal soils, microeukaryotes, genetic diversity, proteo-bacteria, saline-alkaline stress
Address for correspondence: Kuidong Xu. Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China; e-mail: kxu@qdio.ac.cn |
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