Molecular cloning and expression analysis of an F-box protein gene responsive to plant hormones in Brassica napus

F-box protein family is characterized by an F-box motif that has been shown to be critical for the controlled degradation of regulatory proteins. In plant, F-box protein plays an important role in signal pathways and involved in various signal transduction systems. A full-length cDNA encoding a putative F-box protein, designated as BnSLY1, was isolated from Brassica napus. The full-length cDNA of BnSLY1 was 809 bp containing a 438 bp open reading frame encoding a precursor protein of 138 amino acid residues. Comparative and bioinformatic analyses revealed that BnSLY1 showed high degree of homology with F-box proteins from other plant species and contained F-box, GGF and LSL conserved motifs. The expression of BnSLY1 under exogenous gibberellins acid-3 (GA₃), abscisic acid (ABA) and GA biosynthetic inhibitor paclobutrazol (PAC) was analyzed using real-time PCR. The results showed that the expression of BnSLY1 was down-regulated after GA₃ treatment and prominently induced by ABA in the low concentrations. Moreover, BnSLY1 was also induction in the high concentrations of PAC. These results suggest that the expression of BnSLY1 was regulated by the exogenous GA₃, ABA and PAC and may be related to endogenous level of GA in B. napus.