Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Evolutionary pathway of acidihalobacter from a halophile to an acidihalophile (93931)

Katelyn Boase 1 , Carolina González 2 , Eva Vergara 3 , Gonzalo Neira 3 , David Holmes 3 4 , Elizabeth Watkin 5
  1. Curtin Medical School , Curtin University, Perth, Western Australia, Australia
  2. Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
  3. Center for Bioinformatics and Genome Biology, Fundacion Ciencia y Vida and Faculty of Biological Sciences, Andres Bello University, Santiago, Chile
  4. Facultad de Medicina y Ciencias, Universidad San Sebastián, Santiago, Chile
  5. School of Science, Edith Cowan University, Joondalup, WA, Australia

Acidihalobacter is a unique genus of iron- and sulfur- oxidising acidophilic known for its ability to oxidize pyrite minerals in the presence of elevated chloride ions[1,2]. Currently, four species of the Acidihalobacter genus have been identified: A. prosperus, A. yilgarnensis, A. aeolianus and A. ferrooxydans. Previous research has focused on the genetic arsenal that allows Acidihalobacter to cope with chloride, metal and oxidative stress[3,4]. In this study we investigated the genetic repertoire that has enabled the Acidihalobacter genus to cope with acidic stress. Phylogenetic analysis shows that the Acidihalobacter genus roots to the Chromatiales class consisting of mostly halophilic microorganisms. We propose gene gain events that enable the Acidihalobacter genus to cope with acid stress. Potential acid tolerance mechanisms include multiple potassium transporters, chloride/proton antiporters, glutamate decarboxylase system, arginine decarboxylase system, urease system, slp genes, squalene synthesis, and hopanoid synthesis. Some of these genes are hypothesized to have entered the Acidihalobacter via vertical decent from an inferred non-acidophilic ancestor, however horizontal gene transfer from other acidophilic lineages is probably responsible for the introduction of many acid resistance genes.

  1. Khaleque HN, Gonzalez C, Johnson DB, Kaksonen AH, Holmes DS, Watkin ELJ. (2020). International Journal of Systematic and Evolutionary Microbiology.;70(12):6226-34.
  2. Khaleque HN, Gonzalez C, Kaksonen AH, Boxah NJ, Holmes DS, Watkin ELJ. (2019). International Journal of Systematic and Evolutionary Microbiology.;69(6):1557-65.
  3. Khaleque HN, Fathollazadeh H, González C, Shafique R, Kaksonen AH, Holmes DS, Watkin ELJ ( 2020). Genes.;11(12).doi: 10.3390/genes11121392
  4. Khaleque HN, González C, Shafique R, Kaksonen AH, Holmes DS, Watkin ELJ. Frontiers in Microbiology. 2019;10(155).