Comparative Study reveals Morphological, Photophysiological, and Transcriptomic Responses to Varied Light Spectra in Two Filamentous Cyanobacteria from the Nostocales Order

Tolypothrix sp. (also known as Fremyella diplosiphon) is a cyanobacteria capable of adapting to different light spectra by adjusting its light-harvesting pigments to synthesize Phycocyanin (PC) under red light (RL) and Phycoerythrin (PE) under green light (GL), a process known as chromatic acclimation (CA). In contrast, Phormidium sp., a cyanobacteria in the same taxonomic order (Nostocales), cannot perform CA and lacks PE production. To investigate differences between these strains, we exposed both to various light spectra (white light, WL; RL; GL) and conduct transcriptomic analysis.