Functional characterization of maize heat shock transcription factor gene <i>ZmHsf01</i> in thermotolerance

Abstract

<i>ZmHsf01</i> had a coding sequence (CDS) of 1176 bp and encoded a protein consisting of 391 amino acids. The homologous analysis results showed that ZmHsf01 and SbHsfA2d had the highest protein sequence identities. Subcellular localization experiments confirmed that ZmHsf01 was localized in the nucleus. <i>ZmHsf01</i> was expressed in many maize tissues. It was up-regulated by HS, and up-regulated in roots and down-regulated in leaves under ABA and H₂O₂treatments. <i>ZmHsf01</i>-overexpressing yeast cells showed increased thermotolerance. In <i>Arabidopsis</i> seedlings, <i>ZmHsf01</i> compensated for the thermotolerance defects of mutant <i>athsfa2</i>, and <i>ZmHsf01</i>-overexpressing lines showed enhanced basal and acquired thermotolerance. When compared to wild type (WT) seedlings, <i>ZmHsf01</i>-overexpressing lines showed higher chlorophyll content and survival rates after HS. Heat shock protein (HSP) gene expression levels were more up-regulated in <i>ZmHsf01</i>-overexpressing <i>Arabidopsis</i> seedlings than WT seedlings. These results suggest that <i>ZmHsf01</i> plays a vital role in response to HS in plant.