Role of nitric oxide in UV-B induced photomorphogenesis through UVR8 signaling pathway

LATORRE, LUCAS; FERNÁNDEZ, BELÉN; CASSIA, R.

Santa Fe

Congreso; Edición virtual. RAFV 2021; 2021

SAFV

UV-B radiation is a component of sunlight, including eingwavelengths from 280nm to 320nm. The ozone layer filters the UV-B, but a small part reaches the Earth?s surface. This radiation serves both as a stressor and a signal for plants. The protein UVR8 is the plant UV-B receptor.Nitric oxide (NO) is a signaling molecule that participates in physiological and stress acclimation responses . Our objective was to find the role of NO in the UV-B induced photomorphogenesis. With that goal, seedlings of Arabidopsis thaliana wild type (WT) and the UVR8 null mutants uvr8-1, were grown 5 days in continuous UV-B (0,5 w/m2), and endogenous NO was measured by fluorescent probe (DAF-FM DA in hypocotyls. Results show that uvr8-1 mutants did not inhibit elongation of hypocotyl in response to UV-B, and had lower levels of NO compared to WT. Moreover, exogenous application of NO recovered the response to UV-B in the uvr8-1 seedlings. These results indicate the involvement of UVR8 signaling pathway in the UV-B triggered NO production and its importance in the inhibition of hypocotyl elongation. Our previous results indicate that nitrate reductase 1 gene (NIA1) which is involved in NO synthesis, is upregulated by UV-B in a UVR8-dependent manner. In addition, in-silico analysis of the UVR8 pathway revealed the existence of potentially S-nitrosylable conserved cysteines in COP1, NIA1 and MYB12. Altogether, this evidence aims to a fundamental role of NO in regulation of UV-B induced photomorphogenesis.