Microbial microdiversification of the Acidithiobacillia class members in a natural acidic watershed

ISSOTA FRANCISCO; ARISAN DILANAZ; ROJAS VILLALOBO CAMILA; DIAZ GONZALEZ FERNANDO; MOYA BELTRAN ANA; TEMPORETTI PEDRO; GIAVENO ALEJANDRA; DIEZ BEATRIZ; QUATRINI RAQUEL

Pucón

Congreso; XLV Congreso Chileno de Microbiología; 2023

Sociedad Chilena de Microbiología

e">Rio Agrio (RA) is a unique natural extreme acidic watercourse of glacio-volcanic origin, located in the Andesmountain range of northern Patagonia. This river features an ample gradient of pH (pH 0.5–8.5),temperature (10-80°C) and conductivity (0.5-500 mS/cm), and hosts a rich diversity of acidophilicprokaryotes, including representatives of the Acidithiobacillia class. In this study, we analysed theoccurrence, distribution, and microdiversity of Acidithiobacillia populations inhabiting the RA, using culturedependent and independent strategies. For this, we recovered genomes from isolates and MAGs frommetagenomes sampled along the RA physicochemical gradient. De novo and reference-based binningmethods were applied to the datasets to recover population-specific reads, using both local and globalreference genomes and MAGs. This allowed us to assess population structure and diversity along thegradient. According to our results, the acidithiobacilli showed a differential distribution along the gradient,being highly abundant in the Upper RA, and also at the springs that source the river, yet rarely furtherdownstream. Up to 10 lineages of the class co-exist in a number of these sites, some with differentialdistribution and varying relative abundances per site, while other lineages show an ample and evendistributions across sites. Clear evidence of local diversification was uncovered in certain linages, includingthe Igneacidithiobacillus and iron oxidizing lineages of Acidithiobacillus. The correlation between theemerging population structure and the physicochemical gradient parameters was analyzed to gain insightsinto the ecological and evolutionary processes that structure and maintain the microbial diversity in thisecosystem. Emerging results indicate that Acidithiobacillia class species use different strategies to adaptto the local characteristics of the habitats along RA.