Río Agrio:microbial diversity across an extremeenvironmental gradient

ISSOTA FRANCISCO; ARISAN D.; MOYA-BELTRAN A.; CASTRO M.; ULLOA RICARDO; CHIACHIARINI P.; GIAVENO A.; CUEVAS M.; PEDROZO, F.; TEMPORETTI, P.; LIMA A.; URBIETA S.; DONATI E.; JHONSON D.; QUATRINI R.

Glasgow

Congreso; 8th Congress of European Microbiologists; 2019

FEMS

Background:TheCopahue-Caviahue-ChanchoCo geothermal (CCCG) system is a natural extremeenvironmentlocated in the Andes mountain. Two hydrothermal springs nearthevolcano crater are the source of an acidic watershed of uniquecharacteristics in South Americanamed Río Agrio (RA). Along its journey fromthe source to Lake Caviahue and downstream, this river features an amplegradient of pH (pH 0.5?8.5), temperature (10-80ºC) and conductivity (0.5-500mS/cm). Previous studies have shown that the CCCG system host a rich diversityof acidophilic prokaryotes, including representatives of theacidithiobacilli. However,little is know about the variability and distribution patterns of the dominanttaxa.Objectives:Directedmetagenomics (DMG) of the RA gradient was used to assess themicrobial distribution,abundance and diversity. These resultswere analyzed in the context of thehydrogeochemical features of the sampling points.Methods:Microbialbiomass was recovered across the basin of the riverfortotal DNA extraction, PCRand amplicon sequencing. Samples were collected at points were variations inpH, temperature and conductivity could be registered. Selective isolation of acidithiobacilliwas pursued for additional marker gene sequencing.Results: Different nicheswere distinguished along the gradient. DMG data generated provided new insightsinto the community structure in these niches and the composition and diversitychanges occurring along the river. The occurrence and distribution patterns of severalmicrobial acidophiles (e.g. Acidithiobacillus)were defined, along with their microdiversity in distinct niches. This worksets the basis for furtherstudies aiming to explore the eco-evolutionaryprocesses that shape this ecosystem.