title: Analysis of cbbL, nifH, and pufLM in Soils from the Sør Rondane Mountains, Antarctica, Reveals a Large Diversity of Autotrophic and Phototrophic Bacteria.
abstract: Cyanobacteria are generally thought to be responsible for primary production and nitrogen fixation in the microbial communities that dominate Antarctic ecosystems. Recent studies of bacterial communities in terrestrial Antarctica, however, have shown that Cyanobacteria are sometimes only scarcely present, suggesting that other bacteria presumably take over their role as primary producers and diazotrophs. The diversity of key genes in these processes was studied in surface samples from the Sør Rondane Mountains, Dronning Maud Land, using clone libraries of the large subunit of ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL, cbbM) and dinitrogenase-reductase (nifH) genes. We recovered a large diversity of non-cyanobacterial cbbL type IC in addition to cyanobacterial type IB, suggesting that non-cyanobacterial autotrophs may contribute to primary production. The nifH diversity recovered was predominantly related to Cyanobacteria, particularly members of the Nostocales. We also investigated the occurrence of proteorhodopsin and anoxygenic phototrophy as mechanisms for non-Cyanobacteria to exploit solar energy. While proteorhodopsin genes were not detected, a large diversity of genes coding for the light and medium subunits of the type 2 phototrophic reaction center (pufLM) was observed, suggesting for the first time, that the aerobic photoheterotrophic lifestyle may be important in oligotrophic high-altitude ice-free terrestrial Antarctic habitats.
authors.affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tahon
authors.affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
authors.forename: Bjorn
authors.initials: B
authors.lastname: Tytgat
authors.affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Stragier
authors.affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium. anne.willems@ugent.be.
authors.forename: Anne
authors.initials: A
authors.lastname: Willems
mesh_terms: D000864:Antarctic Regions; D052818:Autotrophic Processes; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics*; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D017037:Dinitrogenase Reductase / Q000235:genetics*; D052817:Phototrophic Processes; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D017037:Dinitrogenase Reductase; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012273:Ribulose-Bisphosphate Carboxylase
keywords: Antarctica; Bacteria; Clone libraries; RuBisCO; nifH; pufLM