Journal Article

High-level overexpression of the <i>Arabidopsis HsfA2</i> gene confers not only increased themotolerance but also salt/osmotic stress tolerance and enhanced callus growth

Daisuke Ogawa, Kazuo Yamaguchi and Takumi Nishiuchi

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 58, issue 12, pages 3373-3383
Published in print September 2007 | ISSN: 0022-0957
Published online September 2007 | e-ISSN: 1460-2431 | DOI:

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Heat shock transcription factors (Hsfs) are the central regulators of the heat shock (HS) stress response in all eukaryotic organisms. HsfA2 is one of the Arabidopsis class A Hsfs, and the induction of HsfA2 expression in response to HS stress is highest among all 21 Arabidopsis Hsfs. In this study, it is reported that basal and acquired thermotolerance was significantly enhanced in high-level HsfA2-overexpressed transgenic lines (El2Ω::HsfA2) in comparison with wild-type plants. By contrast, the dominant negative mutants of HsfA2 (El2Ω::HsfA2ΔC264) plants displayed reduced thermotolerance. These results indicate that the HsfA2 gene plays a role in the HS stress response. Microarray analysis of the El2Ω::HsfA2 plants identified putative target genes, which included HS stress-inducible genes and other stress-responsive genes. Salt and osmotic stress induced HsfA2 gene expression. In fact, the El2Ω::HsfA2 plants showed enhanced tolerance to these stresses, suggesting that HsfA2 was involved in multiple stress tolerance. El2Ω::HsfA2 plants showed accelerated callus growth from root explants compared with the wild type, unlike the El2Ω::HsfA2ΔC264 plants whose growth was delayed. These observations suggest that HsfA2 plays, in addition to its role in stress tolerance, an important role in cell proliferation.

Keywords: Biomass; callus; heat shock response; Hsf; microarray; osmotic stress; salt stress

Journal Article.  6234 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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