Molecular characterization, transactivation and expression analysis of BeWRKY2 from Bambusa emeiensis

Abstract

The WRKY transcription factors (TFs) are well known for their critical role in numerous physiological processes including growth, development, and defense against abiotic and biotic stresses. However, studies on WRKY TFs from Bambusa emeiensis have not been reported yet. In the current study, a novel gene encoding WRKY protein was cloned and characterized from B. emeiensis. The isolated gene was named as BeWRKY2 (Accession No. KJ462125). The open reading frame (ORF) of 888 bp, encoded a protein of 295 amino acid residues. The multiple protein sequence alignments showed that BeWRKY2 protein owned a typical WRKY domain with a single WRKYGQK conserved sequence and C2H2 type zinc-finger motif; the phylogenetic analysis disclosed that BeWRKY2 positioned with TaWRKY16, ZmWRKY1, ZmWRKY21, AtWRKY7, AtWRKY11, AtWRKY15, AtWRKY17, and AtWRKY21; as a whole these findings suggested that the corresponding belonged to the II-d sub-group of the WRKY TFs family. The transactivation and sub-cellular localization assays unveiled that BeWRKY2 protein exhibited transcriptional activity and expressed in the cell nucleus. Moreover, expression of BeWRKY2 was profiled under abscisic acid (ABA), Polyethylene glycol 6000 (PEG-6000), NaCl, H2O2, and Na2SO4 treatments via quantitative real-time polymerase chain reaction (qRT-PCR). The results displayed that the transcript accumulation of BeWRKY2 significantly increased under all treatments; a significant difference was observed under ABA (p < 0.001) and PEG, NaCl, H2O2, Na2SO4 (p < 0.01) treatments, respectively. Collectively, the outcomes of current research demonstrated that BeWRKY2 is a transcriptional activator, expressed in the cell nucleus and might play a vital role in ABA signaling pathway and abiotic stress tolerance mechanisms in B. emeiensis.