Two cyanobacterial species exhibit stress responses when grown together in visible light or far-red light.

Although most cyanobacteria grow in visible light (VL; = 400-700 nm), some cyanobacteria can also use far-red light (FRL; = 700-800 nm) for oxygenic photosynthesis by performing far-red light photoacclimation. These two types of cyanobacteria can be found in the same environment. However, how they respond to each other remains unknown.

Identification of a Far-Red Light-Inducible Promoter that Exhibits Light Intensity Dependency and Reversibility in a Cyanobacterium.

As the demand for sustainable energy has increased, photoautotrophic cyanobacteria have become a popular platform for developing tools in synthetic biology. Although genetic tools are generally available for several model cyanobacteria, such tools have not yet been developed for many other strains potentially suitable for industrial applications. Additionally, most inducible promoters in cyanobacteria are controlled by chemical compounds, but adding chemicals into growth media on an industrial scale is neither cost-effective nor environmentally friendly.

Use of Quartz Sand Columns to Study Far-Red Light Photoacclimation (FaRLiP) in Cyanobacteria.

Some cyanobacteria can perform far-red light photoacclimation (FaRLiP), which allows them to use far-red light (FRL) for oxygenic photosynthesis. Most of the cyanobacteria able to use FRL were discovered in low visible-light (VL; λ = 400-700 nm) environments that are also enriched in FRL (λ = 700-800 nm). However, these cyanobacteria grow faster in VL than in FRL in laboratory conditions, indicating that FRL is not their preferred light source when VL is available.