Green Alchemy: Mechanisms of Cyanobacterial Photoprotection in the Spotlight

Cyanobacteria, ancient photosynthetic microorganisms, have perfected an intricate defense system against harsh ultraviolet radiation (UVR) and environmental stressors. Their primary defense deploys pigments like chlorophyll-a and carotenoids to absorb and dissipate excess energy, shielding vital cellular structures. Secondary defense strategies introduce non-enzymatic antioxidants like ascorbate and carotenoids, fortifying cyanobacteria against reactive oxygen species triggered by UVR exposure. Moving further, tertiary photoprotection utilizes UV-absorbing compounds, such as scytonemin and mycosporine-like amino acids (MAAs), creating an extra shield against UVR's relentless onslaught during prolonged exposure. Beyond that, quaternary photoprotection engages DNA repair mechanisms through photolyases (PLs), which, activated by blue light, mend DNA lesions caused by UVR. The story takes an intriguing twist with cyanobacteria's responses to UVR-induced stress, including programmed cell death (PCD). Caspase-like protease activity and metacaspases (MCAs) suggest a fine balance between cell death and survival. In conclusion, this comprehensive odyssey through cyanobacterial photoprotection mechanisms unveils the adaptability and resilience that cyanobacteria have meticulously honed over millions of years. These ancient microorganisms continue to inspire awe as they thrive in a diverse range of ecosystems, shedding light on the enduring marvels of life's adaptability and ingenuity. “Green Alchemy: Mechanisms of Cyanobacterial Photoprotection in the Spotlight” illuminates the intricate strategies that cyanobacteria have honed over millions of years, offering a glimpse into the resilience and adaptability of these remarkable microorganisms. Key words: Photoprotection, Mechanisms, Cyanobacteria & Ultraviolet radiation (UVR)