Oxygen and the Evolution of Acidophiles

Frontiers of Modern Microbiology Seminar Series

Eric Boyd, Assistant Professor, Department of Microbiology and Immunology, Montana State University, Bozeman, MT

Oxygen dependent microbial oxidation of sulfur compounds leads to the acidi-fication of natural waters. These acidic environments are oases of microbial diversity and have conditions that select for a suite of unique taxa with adaptations that allow them to cope with chronic energy and oxidative stress. Here, we show that hypera-cidic (pH < 3.0) volcanic ecosystems are dominated by a limited number of archaeal lineages which exhibit a near universal ability to use oxygen in high energy yielding respiratory metabolisms. Phylogenomic analyses of 584 available archaeal genomes reveals that acidophily evolved independently multiple times and that these events likely occurred in the recent geologic past. The genomes of archaeal acidophiles are enriched in similar protein-coding genes, consistent with convergent evolution aided by horizontal gene transfer. Since the development of acidic environments and their successful habitation both require oxygen, we interpret these results to indicate that acidophilic archaea and their acidic habitats co-evolved and that this occurred after the evolution of oxygenic photosynthesis.

Friday, Nov. 4 | 11 a.m. - noon
Biodesign Auditorium, B105
Biodesign Institute B