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The Heat Shock Factor A4A confers salt tolerance and is regulated by oxidative stress and the Mitogen-Activated Protein kinases, MPK3 and MPK6

Salamo Perez, Immaculada and Papdi, Csaba and Rigó, Gábor and Zsigmond, Laura and Vilela, B. and Nagy, István and Horváth, Balázs and Domoki, Mónika and Darula, Zsuzsanna and Medzihradszky F., Katalin and Koncz, Csaba and Szabados, László (2014) The Heat Shock Factor A4A confers salt tolerance and is regulated by oxidative stress and the Mitogen-Activated Protein kinases, MPK3 and MPK6. PLANT PHYSIOLOGY, 165. pp. 319-334. ISSN 0032-0889

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Abstract

Heat-shock factors (HSFs) are principal regulators of plant responses to several abiotic stresses. Here we show that estradiol-dependent induction of HSFA4A confers enhanced tolerance to salt and oxidative agents, whereas inactivation of HSFA4A results in hypersensitivity to salt stress in Arabidopsis. Estradiol-induction of HSFA4A in transgenic plants decreases, while the knockout hsfa4a mutation elevates hydrogen peroxide accumulation and lipid peroxidation. Overexpression of HSFA4A alters the transcription of a large set of genes regulated by oxidative stress. In yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays HSFA4A shows homomeric interaction which is reduced by alanine replacement of three conserved cysteine residues. HSFA4A interacts with mitogen-activated protein kinases MPK3 and MPK6 in yeast and plant cells. MPK3 and MPK6 phosphorylate HSFA4A in vitro on three distinct sites, Ser309 being the major phosphorylation site. Activation of the MPK3 and MPK6 MAPK pathway led to the transcriptional activation of the heat-shock protein gene HSP17.6A. In agreement that mutation of Ser309 to alanine strongly diminished phosphorylation of HSFA4A, it also strongly reduced the transcriptional activation of HSP17.6A. These data suggest that HSFA4A is a substrate of the MPK3/6 signalling and it regulates stress responses in Arabidopsis.

Item Type: Article
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia
SWORD Depositor: MTMT SWORD
Depositing User: MTMT SWORD
Date Deposited: 24 Sep 2014 22:35
Last Modified: 24 Sep 2014 22:35
URI: http://real.mtak.hu/id/eprint/16554

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