Capsicum Heterotrimeric G Proteins are Up-Regulated under UV-B Radiation Stress

1Heterotrimeric G-proteins (G proteins) constitute a classical signal transduction system which can operate together with G-protein coupled receptors (GPCRs) and regulators of G-protein signaling (RGS) in environmental stress-related pathways. Among several environmental factors that can cause stress in plants, ultraviolet B (UV-B) radiation affects many aspects of plant physiology and activating diverse signaling pathways. Signaling response of Capsicum plants to UV-B radiation has not been studied well. In this study, we studied the expression profile of G proteins, GPCR and RGS genes from stems and roots of Capsicum plants subjected to stress with 1, 2, 3, 6, 12, 18, 25 and 30 h of UV-B radiation. CaGal and CaG beta 1 genes exhibited an increased expression after 18 h of UV-B radiation treatment in stems, while CaG gamma 1, CaG gamma 2, CaRGS1 and CaGPCR genes showed no significant changes in expression. In roots, CaG alpha 1 and CaRGS1 genes showed an increasing expression profile after 3, 18 and 25 h after UV-B radiation but its expresion was not statistically significant. Signaling response to UV-B-radiation in Capsicum was mediated by G proteins in a specific-tissue manner where CaG alpha 1 and CaG beta 1 have an active role in stems. The expresion profiles found in this study were associated with UV-B induced responses in plants, however, the specific roles of G protein members induced by UV-B radiation in Capsicum remains to be elucidated. These results provide evidence of possible role of G protein signaling system in response to UV-B radiation in Capsicum, open for new insights about the search of new genes to be used as molecular markers for manipulation to enhance UV-B radiation stress tolerance in crop plants. (C) 2018 Friends Science Publishers