Cloning and Expression Analysis of WRKY33 Transcription Factor Gene in Brassica juncea
Yuan Yuhui, Wang Kehong, Hua Zhimeng, Peng Yulin, Nie Manqi, Liu Xianjun*
In plants, WRKY gene family, one of the largest families of transcription factors, play an important regulatory role in abiotic stress response. In this study, the full open reading frame (ORF) sequence of BjWRKY33 gene was cloned by reverse transcription polymerase chain reaction (RT-PCR) from Brassica juncea, which was named as BjWRKY33. The sequence was analyzed by bioinformatics tools. The expression characteristics of BjWRKY33 gene were identified by qRT-PCR. The open reading frame of BjWRKY33 gene contained 1 470 bp that encoded 489 amino acids. It is predicted that molecular weight of BjWRKY33 was 54.036 kDa, which had an isoelectric point of 8.56. This protein lacked the signal peptides and membrane-spanning domains. The secondary and tertiary protein structures were predicted, which consisted of 76.89% random coils, 10.43% α-helices, 10.22% extended strands, and 2.45% β-turns. Phylogenetic analysis illustrated that BjWRKY33 had high similarity to the WRKY33 of Cruciferous plants such as Brassica napus, Brassica rapa and Brassica oleracea. The results of fluorescence quantitative PCR analysis revealed that BjWRKY33 was expressed in roots, stems, leaves, buds, flowers and siliques, and the lowest expression was found in stems and buds. Higher expression of BjWRKY33 in leaves was induced by the treatments of the hormone (ABA), low temperature (4 °C) or salt (NaCl). These results indicated that BjWRKY33 might play an important role in maintaining normal growth and development of plants and responding to abiotic stresses.
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