The genomic sequence of Exiguobacterium chiriqhucha str. N139 reveals a species that thrives in cold waters and extreme environmental conditions

PeerJ. 2017 Apr 19:5:e3162. doi: 10.7717/peerj.3162. eCollection 2017.

Abstract

We report the genome sequence of Exiguobacterium chiriqhucha str. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of the Exiguobacterium genomes available suggest that our strain belongs to the same species as the previously reported E. pavilionensis str. RW-2 and Exiguobacterium str. GIC 31. We describe this species and propose the chiriqhucha name to group them. 'Chiri qhucha' in Quechua means 'cold lake', which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bp E. chiriqhucha str. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that confer E. chiriqhucha str. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals, high ultraviolet B radiation, scavenging for phosphorous and coping with high salinity. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina.

Keywords: Arsenic resistance; Bacterial metabolism; Exiguobacterium; Extremophiles; High altitude Andean lakes; Metals or metalloids; Tryptophan biosynthesis; UV resistance.

Grants and funding

AGP was supported by SECITI Postdoctoral Fellowship 029/2013, and at present she is a recipient of a junior postdoctoral contract in the Prometeo Program from the Gobierno Valenciano; CVC by a fellowship from CONACyT Mexico (462083); MRP by the EU Marie Curie Initial Training Network (ITN) Symbiomics: Molecular ecology and evolution of bacterial symbionts [FP7-PEOPLE-2010-ITN]; OFO is a recipient of a Postdoctoral Fellowship from Bunge and Born Foundation; TRP is funded by a Postdoctoral Fellowship from CONACyT Mexico; JVA is supported by a fellowship from CONACyT Mexico (207187); EAR is funded by a NSF grant 1136602. This work was also supported by BFU2015-64322-C2-1-R (co-financed by FEDER funds and Ministerio de Economía y Competitividad, Spain) and PrometeoII/2014/065 (Conselleria d’Educació, Generalitat Valenciana, Spain) to AL and AM, respectively; and by a grant from WWF-Alianza Carlos Slim to VS. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.