ZmHsf05, a new heat shock transcription factor from Zea mays L. improves thermotolerance in Arabidopsis thaliana and rescues thermotolerance defects of the athsfa2 mutant.

High temperature directly affects the yield and quality of crops. Plant Hsfs play vital roles in plant response to heat shock. In the present study, ZmHsf05 was isolated from maize (Zea mays L.) using homologous cloning methods. The sequencing analysis demonstrated that CDS of ZmHsf05 was 1080 bp length and encoded a protein containing 359 amino acids. The putative amino acid sequence of ZmHsf05 contained typical Hsf domains, such as DBD, OD, NLS and AHA motif. Subcellular localization assays displayed that the ZmHsf05 is localized to the nucleus. ZmHsf05 was expressed in many maize tissues and its expression level was increased by heat stress treatment. ZmHsf05 rescued the reduced thermotolerance of the athsfa2 mutant in Arabidopsis seedlings. Arabidopsis seedlings of ZmHsf05-overexpressing increased both the basal and acquired thermotolerances. After heat stress, the ZmHsf05-overexpressing lines showed enhanced survival rate and chlorophyll content compared with WT seedlings. The expression of Hsps was up-regulated in the ZmHsf05-overexpressing Arabidopsis lines after heat stress treatment. These results suggested that ZmHsf05 plays an important role in both basal and acquired thermotolerance in plants.