Community succession of bacteria and eukaryotes in dune ecosystems of Gurbantünggüt Desert, Northwest China

Abstract

Pyrosequencing and quantitative polymerase chain reaction of small subunit rRNA genes were used to provide a comprehensive examination of bacterial, cyanobacterial, and eukaryotic communities in the biological soil crusts (BSCs) of Gurbantünggüt Desert sand dunes (China). Three succession stages were recognized based on the analyses of eukaryotic communities: a late succession stage of BSCs in a swale with eukaryotes mainly related to the Bryophyta clade, an initial succession stage in a slope with barely any eukaryotic phototrophic microorganisms detected, and an intermediate succession type detected from both the swale and slope BSCs dominated by the phylum Chlorophyta. Moreover, the cyanobacterial community dominated all of the BSCs (48.2-69.5 % of the total bacteria) and differed among the three succession stages: sequences related to Microcoleus steenstrupii and the genus Scytonema were abundant in the later succession stage, whereas both the initial and intermediate stages were dominated by Microcoleus vaginatus. Compared with swales, BSCs from slopes are exposed to a harsher environment, e.g., higher irradiance and lower water availability, and thus may be restricted from developing to a higher succession stage. Other disturbances such as wind and grazing may explain the different succession stages observed in swales or slopes. However, no clear differences were detected from non-phototrophic bacterial communities of the three succession stages, and sequences related to Alphaproteobacteria and Actinobacteria were most abundant in all the BSCs. The closest matches for the most frequent non-phototrophic bacterial genera were mainly derived from harsh environments, indicating the robustness of these genera.

Actinobacterial Rare Biospheres and Dark Matter Revealed in Habitats of the Chilean Atacama Desert

“…Pyrosequencing data for microbiota diversities in other world deserts show significant variations in the occurrence of actinobacteria. Thus, sandy Asian deserts such as the Gobi, Gurbantünggütt and Taklamaken are reported to have small (2–18%) actinobacterial communities 29 , 30 . In contrast, soils of certain western deserts such as the Atacama and Sonoran are heavily dominated by actinobacterial phylospecies (75–88% 13 , 19 ).…”

Namib Desert dune/interdune transects exhibit habitat-specific edaphic bacterial communities

“…A total of 30 bacterial phyla were detected in Namib Desert dune soils and all samples were dominated by Proteobacteria, Actinobacteria , and Bacteroidetes , which has also been observed in other desert systems (Makhalanyane et al, 2015 ). Namib Desert dune samples showed similar phylogenetic profiles to dune systems from the Gobi (Mongolia) and Taklamaken (China) deserts (An et al, 2013 ), but with lower OTU diversity than dune slope and interdune of the Gurbantunggut (China) desert (Li et al, 2015 ). The latter, however, was characterized by cyanobacteria-rich biological soil crusts (BSC), which were not observed in the Namib Sand Sea at the time of sampling.…”

Microbial Characterization of Qatari Barchan Sand Dunes

“…Very little is known about the microbiology of Barchan dunes [ 29 ], though stationary dunes [ 13 , 23 – 28 ], and desert soils have been previously studied by others [ 12 , 15 – 22 , 25 ]. Our results provide the first metagenomic and deep 16S rRNA gene amplicon sequencing analysis of microbes from multiple mobile sand dunes in the same dune field and the first quantitative assessment of microbes in Qatari barchan dunes.…”

“…While that work provided important insights into the bacterial diversity of their sand dune, their clone library analysis was limited (89 total), as it predated next generation sequencing efforts. More recently, others [ 13 , 25 , 26 , 28 ] have performed deep 16S rRNA gene amplicon sequencing from dunes in the Gurbantunggut, Namib, Gobi and Taklamaken deserts, though they did not perform culture-based analysis on those sands. In addition to Proteobacteria , Actinobacteria and Bacteroidetes , Cyanobacteria were highly abundant in the Gurbantunggut sands due to the presence of BSCs [ 13 , 26 ].…”

“…Cloning and sequencing of 16S rRNA genes amplified from sand genomic DNA revealed similar results. More recently, others [ 13 , 25 , 26 , 27 , 28 ] have performed sequencing of 16S rRNA gene amplicons from dunes in the Gurbantunggut, Namib, Gobi and Taklamakan deserts. In addition to Proteobacteria , Firmicutes , Actinobacteria and Bacteroidetes , Cyanobacteria were also abundant in the Gurbantunggut sands due to the presence of Biological Soil Crusts (BSCs) [ 13 , 26 ].…”