Pseudomonas cuatrocienegasensis sp. nov., isolated from an evaporating lagoon in the Cuatro Cienegas valley in Coahuila, Mexico

Abstract

Nine Gram-negative, rod-shaped, non-spore-forming isolates with identical or very similar repetitive-sequence-based PCR profiles were recovered from an evaporative lagoon in Mexico. In the present study, a polyphasic approach was undertaken to determine the taxonomic status of nine isolates recovered from an evaporative lagoon in the Churince system, a hydrological system in the Cuatro Ciénegas valley in Coahuila, Mexico (26 u 50.8309 N 102 u 09.3359 W).A large collection of bacterial isolates was obtained from surface water samples collected at two different points (10 m apart) in the lagoon referred to as Laguna Grande. Water samples (15 ml) from each site were collected in sterile BD Falcon vials (BD Biosciences) and 200 ml from each sample was inoculated on glutamate/starch/phenol red (GSP) agar plates (Kielwein, 1971). The GSP medium had the following composition (g l 21): sodium L-(+)-glutamate, 10.0; starch (soluble), 20.0; potassium dihydrogen phosphate, 2.0; magnesium sulfate, 0.5; phenol red, 0.36; agar-agar, 12.0). Incubation was performed at 29 u C for 48 h. Colonies grown on different GSP plates were purified by subculture on Luria-Bertani (LB) agar (1 % tryptone, 0.5 % yeast extract, 1 % NaCl and 1.5 % agar) plates and the cultures were maintained at 280 u C in LB broth (1 % tryptone, 0.5 % yeast extract and 1 % NaCl) with 20 % (w/v) glycerol prior to analysis.The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA sequences of strains 1NT and 3N are EU791281 and EU791282, respectively.A figure showing a pulsed-field electrophoresis gel of novel strains described in this work and type and reference strains of known Pseudomonas species is available with the online version of this paper.

Diversity of culturable thermo-resistant aquatic bacteria along an environmental gradient in Cuatro Ciénegas, Coahuila, México

“…Surprisingly, many CCB microbial taxa have not been previously described from other sites of the world and most of them show divergence with known species at the 16S rRNA level and in an ample array of markers and metabolic functions (Souza et al 2006;Escalante et al 2009;Cerritos et al 2008;Desnues et al 2008;Alcaraz et al 2008). Several environmental factors are likely responsible for the observed high level of microbial diversity, including: long term geological preservation of the site (Taylor 1966;Meyer 1973;Minckley and Jackson 2008;Szynkiewicza et al 2009), spatial heterogeneity and temporal fluctuation (Escalante et al 2008) and finally the result of a panoply of ancient adaptations to the extreme oligotrophy of the site .…”

The Cuatro Ciénegas Basin in Coahuila, Mexico: An Astrobiological Precambrian Park

“…Rather than islands of land surrounded by water, the CCB is an oasis where islands of water are surrounded by desert, all contained in a mountain-ringed basin. These biogeographic barriers have likely been the driver for speciation and diversification of the over 70 endemic species, including diatoms (Winsborough et al, 2009), snails ( Johnson, 2005, fish (Carson and Dowling, 2006;Tobler and Carson, 2010), and more recently bacteria (Escalante et al, 2009;Cerritos et al, 2011). It is intriguing to postulate that endemism is present in the microbiota of the CCB, but an isolate of Bacillus, B. coahuilensis, appears to have adaptive elements unique to the CCB in its genome .…”

Travel, Sex, and Food: What's Speciation Got to Do with It?

“…The geographic isolation occurs at small scales and, as a result and despite higher-level similarities (i.e., similar marine-related taxa), each site is different at increasing resolution from the other sampled sites (Desnues et al, 2008;Breitbart et al, 2009;Escalante et al, 2009;BonillaRosso et al, 2012 in this issue;Rebollar et al, 2012). In fact, in the CCB we observe an increase in both gamma and beta diversity (the slope in the taxa-area power function) as we increase the sampling area.…”

“…The most plausible explanation for this apparent genetic relict of a marine life is the geographic evidence for previous ancient oceans that entered the region 200 million years ago (Alcaraz et al, , 2010Desnues et al, 2008;Moreno-Letelier et al, 2011Peimbert et al, 2012 in this issue). However, molecular clock estimation places some of the constituents of the CCB to a divergence event in the Precambrian 800 million years ago (Domínguez-Escobar et al, 2011;Moreno-Letelier et al, 2011) with subsequent colonization in the area as well as with a consistent and ongoing local speciation and diversification in the microbial community, including viruses (Desnues et al, 2008), bacteria (Escalante et al, 2008(Escalante et al, , 2009Cerritos et al, 2011;Rebollar et al, 2012), and diatoms (Winsborough et al, 2009). Thus, a significant portion of the CCB microbiota appears to have evolved from these relict ancestral marine taxa to form the extant and continuously diversifying local biota that defines a highly endemic CCB biogeographic region.…”