About this Research Topic
Ever since the dawn of life microbial sulfur cycling has profoundly influenced Earth’s biogeosphere, yet many aspects of the sulfur cycle and the microorganisms involved in it are not completely understood. Modern sulfur microorganisms use a wide variety of inorganic and organic sulfur compounds and continue to have significant impact on their living environments - be it in oceanic, freshwater, and terrestrial ecosystems or the bodies of their eukaryotic hosts. Microbial redox reactions of sulfur compounds are tightly interwoven with redox reactions of compounds containing other elements, such as carbon and nitrogen, and translate into interdependent element cycles on a global scale that, e.g., determine greenhouse gas fluxes to the atmosphere and the global climate. On the scale of an individual plant, animal or human, they determine physiological host-microbiota interactions, such as exchange of nutrients/energy and susceptibility of the host to colonization by pathogens.
Acknowledging the importance of sulfur microbiology research, Frontiers in Microbiology has previously released a collection of publications in a research topic on The Microbial Sulfur Cycle (Klotz et al. 2011). Since then a number of exciting discoveries have been made, including ‘cable bacteria’ that couple oxygen reduction at the surface of marine sediments to sulfide oxidation in deeper layers, unexpected sulfur physiologies in marine anaerobic methane oxidation, sulfoglycolysis - a new organo-sulfur metabolism, various tetrathionate reduction mechanisms in enteric pathogens, and sulfur oxidation genes in ocean viruses that might selectively manipulate the metabolism of their microbial hosts. This selection of highlights is testimony to the recent progress in identifying new sulfur microbes, new microbial sulfur metabolisms and their impact on global biogeochemical cycles. These findings have also brought up new research questions. Ongoing and future research on the various facets of microbial sulfur metabolism from the sub-cellular to ecosystem/host level will continue to improve our understanding on how sulfur microorganisms influence ecosystem functioning and host health. This is important in order to exploit or manipulate metabolic activities of sulfur microorganisms for biotechnological/biomedical applications and for maintaining a healthy environment.
This Frontiers research topic should attract contributions from researchers broadly interested in microbial sulfur physiology and sulfur cycling, including, but not limited to, genetics, biochemistry, and regulation of sulfur metabolic pathways, diversity, biogeography and activities of sulfur microorganisms in modern environments, sulfur microorganisms in biotechnological applications, evolution, sulfur isotope fractionation and biogeochemistry, and role of sulfur microorganisms as symbionts of plants, animals, humans, and other eukaryotic hosts.
Klotz MG, Bryant DA and Hanson TE (2011) The microbial sulfur cycle. Front. Microbio. 2:241. doi: 10.3389/fmicb.2011.00241