Isolation and characterization of a G protein γ subunit gene responsive to plant hormones and abiotic stresses in Brassica napus L

Abstract

G protein plays an important role in signaling pathways and is involved in various signal transduction systems in plant. A full-length cDNA encoding a putative G protein γ subunit (Gγ), designated as BnGG2, was isolated from Brassica napus L. BnGG2 is predicted to encode a precursor protein of 100 amino acid residues. The expression of BnGG2 in different B. napus tissues and developmental stages was analyzed by using real-time PCR. The results showed that BnGG2 expression level was high at the 7-day-old seedling stage, the bolting stage, and the fruiting stage. Moreover, BnGG2 was analyzed under four different plant hormones. All of the four tested hormones, abscisic acid (ABA), gibberellins acid 3 (GA3), brassinosteroid (BR) and indole-3-acetic acid (IAA), triggered an induction of BnGG2 expression at different hormone concentrations. The expression of BnGG2 was significantly induced by the high concentrations of ABA, BR, and IAA. The expression of BnGG2 was also induced by low GA3 concentrations and inhibited by high GA3 concentrations. In addition, BnGG2 was responsive to different abiotic stresses. The BnGG2 was up-regulated in salt and drought stress and down-regulated in heat and cold stress. These results suggested that BnGG2 plays an important role in plant hormone signaling pathways and may be also involved in plant defense systems against environmental stresses in B. napus.