Int. J. Mol. Sci. 2014, 15(2), 2517-2537; doi:10.3390/ijms15022517
Article

Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress

email and †,* email
Received: 11 December 2013; in revised form: 17 January 2014 / Accepted: 28 January 2014 / Published: 13 February 2014
(This article belongs to the Special Issue Redox Signaling in Biology and Patho-Biology)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: In any living species, stress adaptation is closely linked with major changes of the gene expression profile. As a substrate protein of the rapidly stress-induced mitogen-activated protein kinase MPK3, Arabidopsis transcription factor MYB44 likely acts at the front line of stress-induced re-programming. We recently characterized MYB44 as phosphorylation-dependent positive regulator of salt stress signaling. Molecular events downstream of MYB44 are largely unknown. Although MYB44 binds to the MBSII element in vitro, it has no discernible effect on MBSII-driven reporter gene expression in plant co-transfection assays. This may suggest limited abundance of a synergistic co-regulator. MYB44 carries a putative transcriptional repression (Ethylene responsive element binding factor-associated Amphiphilic Repression, EAR) motif. We employed a dominant repressor strategy to gain insights into MYB44-conferred stress resistance. Overexpression of a MYB44-REP fusion markedly compromised salt and drought stress tolerance—the opposite was seen in MYB44 overexpression lines. MYB44-mediated resistance likely results from induction of tolerance-enhancing, rather than from repression of tolerance-diminishing factors. Salt stress-induced accumulation of destructive reactive oxygen species is efficiently prevented in transgenic MYB44, but accelerated in MYB44-REP lines. Furthermore, heterologous overexpression of MYB44-REP caused tissue collapse in Nicotiana. A mechanistic model of MAPK-MYB-mediated enhancement in the antioxidative capacity and stress tolerance is proposed. Genetic engineering of MYB44 variants with higher trans-activating capacity may be a means to further raise stress resistance in crops.
Keywords: abiotic stress; mitogen-activated protein kinase (MAPK); reactive oxygen species; MYB; repression motif; Arabidopsis
PDF Full-text Download PDF Full-Text [1735 KB, uploaded 19 June 2014 05:27 CEST]

Export to BibTeX |
EndNote


MDPI and ACS Style

Persak, H.; Pitzschke, A. Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress. Int. J. Mol. Sci. 2014, 15, 2517-2537.

AMA Style

Persak H, Pitzschke A. Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress. International Journal of Molecular Sciences. 2014; 15(2):2517-2537.

Chicago/Turabian Style

Persak, Helene; Pitzschke, Andrea. 2014. "Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress." Int. J. Mol. Sci. 15, no. 2: 2517-2537.


Int. J. Mol. Sci. EISSN 1422-0067 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert