UV-B radiation and temperature stress-induced alterations in metabolic events and defense mechanisms in a bloom-forming cyanobacterium Microcystis aeruginosa

• Published in: Acta physiologiae plantarum 2017-11, Vol.39 (11), p.1-11, Article 248
• Main Authors: Babele, Piyoosh K., Singh, Garvita, Singh, Anjali, Kumar, Ashok, Tyagi, Madhu B., Sinha, Rajeshwar P.
• Format: Article
• Language: English
• Subjects: Agriculture; Amino acids; Ascorbic acid; Biomedical and Life Sciences; Catalase; Climate change; Climatic conditions; Defense mechanisms; Deoxyribonucleic acid; DNA; DNA damage; Forming; L-Ascorbate peroxidase; Life Sciences; Lipids; Microcystis; Microcystis aeruginosa; Mycosporine-like amino acids; Original Article; Peroxidase; Photosynthesis; Photosynthetic pigments; Pigments; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Proline; Proteins; Reactive oxygen species; Shinorine; Stresses; Superoxide dismutase; Survival; Temperature effects; Ultraviolet radiation
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-017-2540-4

The present investigation is aimed to understand how a bloom-forming cyanobacterium Microcystis aeruginosa adapts to changing climatic conditions. The cyanobacterium was exposed to stresses of UV-B (2 Wm −2 ) radiation and temperature (45 °C) for desired time intervals. Results showed that both the stresses affect growth and photosynthetic efficiency of M. aeruginosa . More than 50% loss of survival and content of photosynthetic pigments was noted after 4 h treatment of both the above stresses. Such changes were mainly due to the generation of reactive oxygen species which cause damage to proteins, DNA, lipids, and modulation of the membrane stability. An increase in the proline accumulation was noted in the cells which probably negates the harmful effects. In addition, activity of antioxidative enzymes namely, catalase, superoxide dismutase, ascorbate peroxidase, and peroxidase was induced by 1.5–3.0-fold on 3 h of UV-B and temperature treatment indicating their possible role in protection. Interestingly, induction of photoprotective compound, mycosporine-like amino acids (MAAs) were also found under UV-B stress which might be an additional strategy of defense mechanism for the survival of the cyanobacterium. Analysis of photoprotective compound revealed shinorine as the main MAA synthesized by the cyanobacterium.