Actinobacterial community and ionic composition in sediment of Xinjiang saline lakes: Barkol, Qijiaojing and Taitema

Abstract:

[Objective] The aim of this study was to investigate actinobacterial diversity in the sediment of Xinjiang saline lakes: Taitema, Barkol and Qijiaojing, and the relationship between the actinobacterial community and ionic composition. [Methods] From every lake we collected 5 samples and mixed, to extract total DNA by using SDS-CTAB. We used primers for the class Actinobacteria for actinobacterial l6S rRNA gene amplification and then constructed a clone library for the sediment sample. In total 220 clones were randomly selected from each sample, from which the positive clones were screened on the basis of Hae III digestion patterns, and then these positive clones were sequenced. Eight major chemical ions were detected in each sample, and then the correlation between chemical ions and actinobacterial community was analyzed. [Results] In total 143 Operational Taxonomic Units (OTUs) were obtained from 381 clones which belonged to 37 actinobacterial genera (Taitema: 24, Barko: 16, Qijiaojing: 14). The common Actinobacteria of the three lakes were Aciditerrimonas, Aquihabitans, Demequina, Dietzia, Ilumatobacter and Amycolatopsis. Barkol was closer to Qijiaojing at the actinobacterial community composition, but Taitema had huge difference from the other two. There were plenty of unknown Actinobacteria in the Sediment of these Lakes, it reached 47.59% in the whole Actinobacteria at Barkol, 53.07% at Qijiaojing and 51.53% at Taitema. Redundancy analysis was used to analyze the relationship between chemical ions and actinobacterial community, and the results showed that Mg2+, Ca2+, SO42-, HCO3- and CO32- had closer ties with the actinobacterial community than Na+, Cl- and K+. [Conclusion] These lakes contained plenty of unknown Actinobacteria which were worth to exploring and different ions influenced unique Actinomycetes community.

Key words:Saline lakes, Ionic composition, Actinobacterial community, Culture-independent