Wheat WRKY transcription factor TaWRKY24 confers drought and salt tolerance in transgenic plants.

ABSTRACT

Drought and salt stress are major environmental conditions that severely limit plant growth and productivity. WRKY transcription factors play a vital role in the responses against biotic or abiotic stress. In this study, TaWRKY24, a gene of the IIe WRKY family identified in wheat, was cloned and characterized. TaWRKY24 was mainly expressed in wheat leaf and stem and induced by treatment with PEG6000, salt, H2O2, ABA, MeJA, and ethrel. TaWRKY24 transient expression in onion epidermal cells suggested its nuclear localization and its transcriptional activation capability characteristics. Overexpression of TaWRKY24 in tobacco improved the seed germination rate and root growth of seedlings in transgenic lines when subjected to higher mannitol and NaCl concentrations. Further research showed that transgenic lines had higher proline and soluble sugars and lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Moreover, compared to normal and negative control plants, TaWRKY24 silenced wheat seedlings had reduced growth under salt and drought stress. This study shows that wheat TaWRKY24 is crucial to plant stress, providing an excellent candidate gene for wheat resistance breeding.