GmWRKY53, a water- and salt-inducible soybean gene for rapid dissection of regulatory elements in BY-2 cell culture

Abstract

Drought is the major cause of crop losses worldwide. Water stress-inducible promoters are important for understanding the mechanisms of water stress responses in crop plants. Here we utilized tobacco (Nicotiana tabacum L.) Bright Yellow 2 (BY-2) cell system in presence of polyethylene glycol, salt and phytohormones. Extension of the system to 85 mM NaCl led to inducibility of up to 10-fold with the water stress and salt responsive soybean GmWRKY53 promoter. Upon ABA and JA treatment fold inducibility was up to 5-fold and 14-fold, respectively. Thus, we hypothesize that GmWRKY53 could be used as potential model candidate for dissecting drought regulatory elements as well as understanding crosstalk utilizing a rapid heterologous system of BY-2 culture.

Keywords: GmWRKY53; abscisic acid; salt stress; tobacco BY-2; water stress.

Figure 1. (A) PEG treated BY-2 cells are alive and express GFP after incubation in medium containing 10% polyethylene glycol. (B) Multiple E-box sequences in the promoter region of the GmWRKY53. Potential promoter elements were identified using MEME.

Figure 2. (A) GUS activity of Nt RS promoter:GUS in 10% mannitol. The figure shows average of three independent experiments involving five independent transgenic lines. The values on the top of black color treated columns shows the average fold induction. GUS assays were performed as previously described. (B) GFP activity of GmWRKY53 promoter: GFP BY-2 in 10% PEG, 0.5% (85 mM) NaCl.,100 µM ABA and 100 µM JA. The figure shows the average of three independent experiments involving five independent transgenic lines and bars represent standard error. The values on the top of black color treated columns shows the average fold induction. The scale bar represents 50 μm for NtRS and GmWRKY53 was used.