Maize (Zea mays L.) homologue of ABA-insensitive (ABI) 5 gene plays a negative regulatory role in abiotic stresses response

Abstract

Abscisic acid serves as an important hormone involved in response to environmental stresses. In this study, a homolog of ABA-insensitive (ABI) 5 gene, named as ZmABI5, has been isolated from maize (Zea mays L.). Expression of ZmABI5 is induced by a wide spectrum of stresses, including abscisic acid, salicylic acid, NaCl, high and low temperature, wounding and mannitol treatments. To identify the function of the ZmABI5 under stress conditions, a binary vector containing ZmABI5 driven by CaMV 35S promoter was constructed and the transgenic tobacco (Nicotiana tabacum) plants over-expressing ZmABI5 were produced by Agrobacterium-mediated transformation. When treated with NaCl, mannitol, high and low temperature, the transgenic plants display obvious stress-sensitive phenotypes. The activity of superoxide dismutase and peroxidase, content of proline in the transgenic plants were obviously lower than that of wild type plants. Malondialdehyde content was higher in the transgenic plants than that of wild type plants. Quantitative PCR analysis showed that over-expression of ZmABI5 altered the expression of GCC box-containing gene PR5, and drought-responsive element/C-repeat (DRE/CRT) genes (CAT1, APX and NtERD10A, B, C, D). These results demonstrate that over-expression of ZmABI5 makes the tobacco plants sensitive to salt, drought, high and low temperature stresses. It suggests that ZmABI5 plays a negative regulatory role in stresses response.