A succinate dehydrogenase flavoprotein subunit-like transcript is upregulated in Ilex paraguariensis leaves in response to water deficit and abscisic acid

RAÚL M. ACEVEDO; SANTIAGO J. MAIALE; SILVINA C. PESSINO; RUBÉN BOTTINI; OSCAR A RUIZ; PEDRO A. SANSBERRO

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2013 vol. 65 p. 48 - 54

0981-9428

Ilex paraguariensis plants were subjected to progressive soil water deficit and differential display (DD) was used to analyse gene expression in leaves to characterise physiological responses to mild and severe water deficits. A cDNA fragment showing strong homology with the flavoprotein subunit of succinate:ubiquinone oxidoreductase (succinate dehydrogenase, SDH1, EC 1.3.5.1) was upregulated in plants exposed to drought. Quantitative real-time PCR revealed that the sdh1-like transcript level began to increase when the leaf relative water content (RWC) decreased to 78% and peaked when the RWC dropped to 57%. A correlation between ABA concentration and variations in transcript levels was assessed by GC-SIM. After rehydration, sdh1 mRNA and ABA returned to their initial levels, and sdh1 mRNA accumulated to greater levels in leaves sprayed with ABA compared to non-sprayed leaves. Moreover, the enzymatic activity of succinate dehydrogenase increased 1.5-fold in the mature leaves of ABA treated plants. This physiological response may be related to the tendency of this species to minimise water losses through stomatal closure in the early stages of dehydration to avoid tissue desiccation. As the leaf water potential diminished along with an increase in water restriction, I. paraguariensis leaf tissues reacted by making osmotic adjustments to sustain tissue metabolic activity, which enables the recovery of photosynthesis upon re-watering. To our knowledge, this is the first report that provides insights regarding the role of mitochondrial complex II in the plant response to water deficit. Additionally, this study establishes a basis for future studies on the physiology of water stress tolerance.