Expression of the Kale WRKY Gene BoWRKY10 in Transgenic Tobacco Confers Drought Stress Tolerance

Abstract

WRKYs play important roles in plant growth, defense regulation, and the stress response. However, the mechanisms through which WRKYs are involved in drought tolerance have been rarely characterized in kale (Brassica oleracea var. acephala DC). In this study, we cloned the BoWRKY10 gene from kale and its expression was induced with PEG4000, NaCl, gibberellic acid, cold, H2O2, and abscisic acid (ABA). Bo-WRKY10 was localized in the nucleus. The protein had a WRKY domain and a C2H2 zinc finger structure and belonged to subgroup II. The analysis of yeast transcriptional activity showed that BoWRKY10 may have transcriptional activation activity, which was mainly determined by the carboxyl terminal sequence. BoW-RKY10-overexpressing tobacco (Nicotiana tabacum L.) showed enhanced drought tolerance. After the drought treatment, relative water content and proline contents as well as superoxide dismutase activity were higher in transgenic plants, while malondialdehyde and H2O2 contents were lower. In addition, several genes related to the ABA signaling pathway, sucrose, and the reactive oxygen species scavenging system, were significantly upregulated in the transgenic lines. These results demonstrate that BoWRKY10 confers drought tolerance in tobacco. These results provide clues regarding the mechanism by which BoWRKY10 contributes to the regulation of drought stress tolerance.