Ectopic Overexpression of Maize Heat Stress Transcription Factor Confers Drought Tolerance in Transgenic Rice.

Drought is a key factor affecting plant growth and development. Heat shock transcription factors () have been reported to respond to diverse abiotic stresses, including drought stress. In the present study, functional characterization of maize heat shock transcription factor 05 ( gene was conducted. Homologous analysis showed that belongs to Class A2 . The mRNA expression level of can be affected by drought, high temperature, salt, and abscisic acid (ABA) treatment. Ectopic overexpression of in rice () could significantly enhance the drought tolerance. Faced with drought stress, transgenic rice exhibited better phenotypic performance, higher survival rate, higher proline content, and lower leaf water loss rate, compared with wild-type plant Zhonghua11. Additionally, we assessed the agronomic traits of seven transgenic rice lines overexpressing and found that altered agronomical traits in the field trials. Moreover, rice overexpressing was more sensitive to ABA and had either a lower germination rate or shorter shoot length under ABA treatment. The transcription level of key genes in the ABA synthesis and drought-related pathway were significantly improved in transgenic rice after drought stress. Collectively, our results showed that ZmHsf05 could improve drought tolerance in rice, likely in an ABA-dependent manner.