NO-mediated responses to UV-B radiation in Arabidopsis thaliana and the cyanobacteria Synechococcus sp. PCC 7335.

LATORRE, LUCAS; FERNÁNDEZ, MARÍA BELÉN; FERNÁNDEZ, GONZALO; CORREA-ARAGUNDE, NATALIA; CASSIA, RAÚL

Simposio; Frontiers in Bioscience 4 Symposium; 2023

Exposure to UV-B radiation damages DNA and alters the metabolism of photosynthetic organisms such as plants and cyanobacteria. However, both have developed mechanisms to mitigate UV-B stress, including the regulation of gene expression, the synthesis of photoprotective compounds and DNA repair. In higher plants, UV-B is sensed by the UVR8 receptor, a master regulator that controls photomorphogenic responses to UV-B. The UVR8 pathway was not found in the cyanobacterial genomes. One of the chemical mediators of UV-B signaling is nitric oxide (NO), which acts as both a cell messenger and an antioxidant molecule. NO is produced either by enzymatic and non-enzymatic pathways in plants and cyanobacteria and modulates the activity of various transcription factors and proteins during UV-B exposition. Therefore, it plays a crucial role in the adaptation and survival of these organisms to oxidative stress and damage caused by this radiation. This work examines the similarities and differences of the UV-B response in the plant Arabidopsis thaliana and the cyanobacteria Synechococcus sp. PCC 7335, and the role of the signaling molecule NO in this process. A. thaliana does not have nitric oxide synthases (NOS), whereas S. PCC 7335 does, and both organisms differ in UV-B photoreception. However, they converge in the production of NO, the augmentation of photolyase transcripts (enzymes that repair DNA damage damages), the repair of DNA damage, and the effects on photosynthetic pigments under UV-B stress. Finally, the comprehension of UV-B related signaling pathways will allow us to understand the evolution of this response among photosynthetic organisms. Supported by Agencia Nacional de Promoción Científica y Tecnológica (ANPCYT), CONICET and Universidad Nacional de Mar del Plata.