Cloning and Expression Analysis of an F-box Gene ( SiFBX ) Rapidly Responsive to Drought Stress

Abstract

F-box proteins, components of the Skp1-Cullin1-F-box(SCF) protein E3 ubiquitin ligase complex, serve as the variable component responsible for substrate recognition and recruitment in SCF-mediated proteolysis. The anti-drought relative gene of SiFBX(GenBank accession number KC252635.1) which belongs to the F-box super family was cloned from foxtail millet(Setaria italic). The full-length cDNA of SiFBX was 510 bp, which encoded 170 amino acid residues. Protein analysis and structure predication showed that it has a higher proportion of arginine(R), leucine(L), and serine(S) and a lack of trans-membrane domains and signal peptide. Phylogenetic analysis demonstrated that SiFBX has similarity with EID1 and FBW4. Many abiotic stress-related cis-acting elements and transcription factors were discovered in the 1.9 kb upstream region of SiFBX. The results of real-time PCR showed that there were remarkable changes in the expectation level of SiFBX for the treatments with PEG, water-withholding, and ABA.