Microbe Thrives In Red-Light District

Just north of Yellowstone National Park, at LaDuke Hot Springs, a blue-green alga (cyanobacterium) makes its home underneath a multilayered mat of microbes. The single-celled community is so dense with life that only far-red wavelengths of light penetrate to the bottom. And yet the Leptolyngbya algal strain JSC-1 perseveres. Scientists have discovered that the microbe can make rapid, drastic changes to its photosynthesis apparatus to enhance light harvesting (Science 2014, DOI: 10.1126/science.1256963). The finding might be exploited by bioengineers seeking renewable energy from sunlight or by microbiologists studying bacteria in remote environments such as desert soils. Researchers have known for roughly 100 years that cyanobacteria adapt to different-colored light sources. But the extremes of far-red light with wavelengths beyond 700 nm set off a different adaptation process, according to Donald A. Bryant of Pennsylvania State University and colleagues. The researchers sequenced JSC-1’s genome and isolated the pigments it produces after growing the microbe in different wavelengths of light. In addition to synthesizing red-light-harvesting chlorophylls, they found that the microbe alters transcription levels for more than 40% of its genome and replaces the core components of its three key photosynthesis protein complexes.