chlL/bchL: gene encoding the L protein (ChlL/BchL) of dark-operative protochlorophyllide reductase (DPOR).
Environmental constraints defining the distribution, composition, and evolution of chlorophototrophs in thermal features of Yellowstone National Park
Article first published online: 28 SEP 2011
© 2011 Blackwell Publishing Ltd
Special Issue: Anaerobic Photosynthetic Ecosystems
Volume 10, Issue 3, pages 236–249, May 2012
How to Cite
HAMILTON, T. L., VOGL, K., BRYANT, D. A., BOYD, E. S. and PETERS, J. W. (2012), Environmental constraints defining the distribution, composition, and evolution of chlorophototrophs in thermal features of Yellowstone National Park. Geobiology, 10: 236–249. doi: 10.1111/j.1472-4669.2011.00296.x
bchY: gene encoding the Y protein (BchY) of chlorophyllide oxidoreductase (COR).
- Issue published online: 4 APR 2012
- Article first published online: 28 SEP 2011
- Received 18 April 2011; accepted 23 August 2011
Chlorophotoautotrophy, the use of chlorophylls to convert light energy into chemical energy for carbon dioxide fixation, is the primary metabolic process linking the inorganic and organic carbon pools on Earth. To understand the potential effects of various environmental constraints on the evolution of chlorophototrophy better, we studied the distribution, diversity, and abundance of chlorophylls and genes involved in their synthesis along geothermal gradients in Yellowstone National Park, Wyoming. Genes involved in chlorophyll biosynthesis were constrained to temperatures of less than ∼70 °C and were only detected at this elevated temperature when the pH was in the circumneutral to alkaline range. The upper temperature limit for the detection of chlL/bchL1 and bchY2 decreased systematically with increasingly acidic pH, an observation likely attributable to sulfide, which upon oxidation, generates acidic spring water and reduces the availability of bicarbonate the preferred source of inorganic carbon for phototrophs. Spring pH was also the best predictor of the phylogenetic diversity of chlL/bchL communities. The phylogenetic similarity of chlL/bchL genes between sites was significantly correlated with that of chlorophylls. The predominance of chlorophyll a and bacteriochlorophyll a among extracted pigments was consistent with predominance of chlL/bchL genes affiliated with the Cyanobacteria and Chloroflexiales, respectively, and might be related to the fact that the majority of these organisms are photoautotrophs. Together, these results suggest that a combination of temperature, pH, and/or sulfide influences the distribution, diversity, and evolution of chlorophotrophs and the chlorophylls that they synthesize.