The Maize AP2/EREBP Transcription Factor ZmEREB160 Enhances Drought Tolerance in Arabidopsis

Drought is a main factor affecting plant growth and crop production. APETALA2/Ethylene Responsive Element Binding Protein (AP2/EREBP) transcription factors (TFs) are involved in the response to abiotic stress and their functions in ABA signaling and the regulation of drought response have been intensively studied. However, AP2/EREBP TFs have been limited in the maize. The objective of our study was to identify the function of the novel maize AP2/EREBP gene ZmEREB160. Expression levels analysis in maize revealed that ZmEREB160 is significantly induced by PEG6000, NaCl and ABA treatment. ZmEREB160 localized to the nucleus when transiently expressed in Arabidopsis leaf protoplasts. ZmEREB160 activated the reporter gene and exhibited transcriptional activation activity in yeast cells. When overexpression of ZmEREB160 in Arabidopsis significantly enhanced tolerance to osmotic and ABA stress, overexpressed seedlings were longer roots under ABA and mannitol treatments compared with wild type. In addition, overexpression of ZmEREB160 Arabidopsis seedlings was found to elevate survival rate compared with wild type plants under drought stress. During the drought treatment, qRT-PCR assays showed that the expression levels of ABA/drought stress-related genes, ABI2, ABI5, COR15, DREB2A and RD29B were up-regulated in ZmEREB160 transgenic plants, transgenic plants accumulated more proline content than wild type plants. These results indicate that ZmEREB160 functions in response to drought and ABA stresses, and participates in ABA signaling pathway and may enhance drought tolerance.