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

ACEVEDO MAXIMILIANO; MAIALE SANTIAGO; PESSINO SILVINA; BOTTINI RUBEN; RUIZ OSCAR; SANSBERRO PEDRO

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  (SDH1)  of  succinate:ubiquinone  oxidoreductase  (succinate  dehydrogenase,  SDH,  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 abscisic acid (ABA) concentration and variations in   transcript  levels  was  assessed  by  GC-SIM.  After  rehydration,  SDH1  mRNA  and  ABA  returned  to  their  initial  levels.  In  stressed  leaves  sprayed  with  ABA  SDH1  mRNA  accumulated  in  greater  levels  compared  to  stressed  leaves  that  did  not  receive  ABA.   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 due  to 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. These results provide new insights concerning the linkage   between plant  respiration and photosynthetic metabolism  that could be potentially  further  used in breeding programs aiming water tolerant genotypes.