abstract
Cork oak is an economically important forest species showing a great tolerance to high temperatures and shortage of water. However, the mechanisms underlying this plasticity are still poorly understood. Among the stress regulators, transcription factors (TFs) are especially important since they can control a wide range of stress-inducible genes, which make them powerful targets for genetic engineering of stress tolerance. Here we evaluated the influence of increasing temperatures (up to 55 C) or drought (18% field capacity, FC) on the expression profile of an R2R3-MYB transcription factor of cork oak, the QsMYB1. QsMYB1 was previously identified as being preferentially expressed in cork tissues and as having an associated alternative splicing mechanism, which results in two different transcripts (QsMYB1.1 and QsMYB1.2). Expression analysis by reverse transcription quantitative PCR (RT-qPCR) revealed that increasing temperatures led to a gradual down-regulation of QsMYB1 transcripts with more effect on QsMYB1.1 abundance. On the other hand, under drought condition, expression of QsMYB1 variants, mainly the QsMYB1.2, was transiently up-regulated shortly after the stress imposition. Recovery from each stress has also resulted in a differential response by both QsMYB1 transcripts. Several physiological and biochemical parameters (plant water status, chlorophyll fluorescence, lipid peroxidation and proline content) were determined in order to monitor the plant performance under stress and recovery. In conclusion, this report provides the first evidence that QsMYB1 TF may have a putative function in the regulatory network of cork oak response to heat and drought stresses and during plant recovery. (C) 2013 Elsevier Masson SAS. All rights reserved.
keywords
TRANSCRIPTION FACTORS; LIGNOTUBER ONTOGENY; GENE-EXPRESSION; DIFFERENT WATER; ARABIDOPSIS; PCR; TEMPERATURE; ADAPTATION; METABOLISM; PLASTICITY
subject category
Plant Sciences
authors
Almeida, T; Pinto, G; Correia, B; Santos, C; Goncalves, S
our authors
Sónia Claudia Morgado Gonçalves
Research Assistant
Tânia Raquel Domingues de Almeida
Post-Doc Fellowshipacknowledgements
This work was supported by FEDER funds through Competitiveness Factors Operacional Program COMPETE and by national funds through Fundacao para a Ciencia e Tecnologia (FCT) in the frame of project PTDC/AGR-GPL/118856/2010. Researchers were also supported by FCT through grants SFRH/BD/44410/2008 to T. Almeida and SFRH/BD/86448/2012 to B. Correia. S. Goncalves and G. Pinto were supported by the Program Ciencia 2008 (FCT), co-funded by the Human Potential Operational Program (National Strategic Reference Framework 2007-2013) and European Social Fund (EU). Authors also thank to Armando Costa and Claudia Jesus (University of Aveiro) for technical support.