Nitric Oxide regulates the stability of the UVR8 photoreceptor in the response of Arabidopsis thaliana to UV-B.

TOSSI, V; DAVILA, V; LAMATTINA, L.; JENKINS, G; CASSIA, R.

Mar del Plata

Congreso; XV lCongreso latinoamericano, XXX Reunion Argentina de Fisiologia Veget; 2014

Sociedad Argentina de Fisiologia Vegetal

UV-B radiation (280-320 nm) is perceived by Arabidopsis through the UV RESISTANCE LOCUS 8 (UVR8) receptor. Nitric oxide (NO) is a multifunctional molecule that participates in adaptive response to stress. Recently, we demonstrated that NO is necessary in the UVR8-mediated response to UV-B, but it is unknown how NO regulates the UVR8 activity. Here, we analyzed the UVR8 protein integrity in UV-B irradiated plants having low NO levels. UVR8 level was diminished in that condition, indicating that NO is important for UVR8 stability. To evaluate if the NO effect is due to a change in redox environment, Arabidopsis plants with low NO levels were treated with different antioxidants, such as ascorbate acid and glutathione before irradiation. UVR8 protein level was restored when plants were treated with antioxidants. In conclusion, UVR8 is susceptible to changes in the redox environment when plants are exposed to UV-B, and NO protects UVR8 from degradation. Moreover, it was reported that NO is able to modify the protein activity through nitrosilación in plants. This posttranscriptional modification could regulate the UVR8 activity. To determine if UVR8 could be nitrosylated, purified UVR8 protein was incubated with a NO donor and subjected to biotin switch assay. We observed that UVR8 was nitrosylated.