A novel Cys2/His2 zinc finger protein gene from sweetpotato, IbZFP1, is involved in salt and drought tolerance in transgenic Arabidopsis

Abstract

IbZFP1, encoding a Cys 2/His 2 zinc finger protein gene from sweetpotato, enhances salt and drought tolerance in transgenic Arabidopsis by regulating ABA signaling pathway, proline biosynthesis, stress responses and ROS scavenging. In plants, Cys2/His2 zinc finger proteins play important roles in regulating the growth and development or responses to abiotic stresses. In this study, a novel Cys2/His2 zinc finger protein gene, named IbZFP1, was isolated from drought-tolerant sweetpotato [Ipomoea batatas (L.) Lam.] line Xu55-2. Subcellular localization analysis in onion epidermal cells indicated that IbZFP1 was localized to the nucleus. Expression analysis in yeast showed that the full length of IbZFP1 exhibited transcriptional activation. Expression of IbZFP1 was induced by NaCl, polyethylene glycol and abscisic acid (ABA). Overexpression of IbZFP1 significantly enhanced salt and drought tolerance in transgenic Arabidopsis plants. Real-time quantitative PCR (qRT-PCR) analysis showed that overexpression of IbZFP1 up-regulated the genes involved in ABA signaling pathway, proline biosynthesis, stress responses, and ROS scavenging under salt and drought stresses. Meanwhile, Western blot and enzymatic analyses showed that the activities of 9-cis-epoxycarotenoid dioxygenase, pyrroline-5-carboxylate synthase, superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase were also increased. Further component analyses indicated that the significant increase of ABA, proline, soluble sugar and total chlorophyll content and the significant reduction of H2O2 and malonaldehyde content were observed under salt and drought stresses. In addition, the rates of electrolyte leakage and water loss were reduced in transgenic plants. The overall results demonstrate the explicit role of IbZFP1 in conferring salt and drought tolerance in transgenic Arabidopsis plants. The IbZFP1 gene has the potential to be used to enhance the tolerance to abiotic stresses in plants.

Keywords: Arabidopsis; Cys2/His2 zinc finger protein; Salt and drought tolerance; Sweetpotato; Transcription factor.