IQUIFIB   02644
INSTITUTO DE QUIMICA Y FISICOQUIMICA BIOLOGICAS "PROF. ALEJANDRO C. PALADINI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
NITRIC OXIDE AND REACTIVE OXYGEN SPECIES RELEASED FROM POLYAMINES ARE PARTIALLY RESPONSIBLE FOR THE INHIBITION OF WHEAT ROOT ELONGATION
Autor/es:
GROPPA M.D.; VÁZQUEZ A.; RECALDE L.; BENAVIDES M.P.
Reunión:
Congreso; XXII Reunión de la Sociedad Española de Fisiología Vegetal; 2017
Resumen:
Polyamines are molecules involved in plant growth and development, able to generate reactive oxygen species (ROS) and nitric oxide (NO) during their catabolism. We examined if ROS and/or NO derived from PAs are implicated in the mechanisms involved in growth inhibition in wheat roots. Triticum aestivum L. seedlings were grown in Hoagland solution containing: 0.1 mM of the NO-donor SNP, 1 mM putrescine (Put), spermidine (Spd) or spermine (Spm). A similar degree of root growth inhibition was detected in plants treated with Spm or SNP for 5 d (around 75 %), while Put less inhibited root growth (about 35 %). The three PAs increased nitric oxide production in the apical portion of primary roots. O2.- was greatly reduced by SNP or Spm, despite both treatments increased H2O2 formation in roots. SNP and Spm significantly reduced (around 50%) O2.--dependent NBT reduction, a way to measure a potential NADPH oxidase activity; only Spd strongly reduced CAT activity (to 40% of the C) whereas SOD was around 25% reduced in SNP or Spm-treated roots but 30% increased in Spd-treated roots. Spm and SNP treatments reduced lipid peroxidation in roots, whereas Put, which was the PAs that less affected growth, raised it by 75%. Putrescine content was doubled in SNP-treated roots and increased between 3 and 4 times in Put and Spd-treated roots, respectively, but increased only 25% in Spm-treated roots. Polyamine oxidase activity, that metabolize Spd or Spm producing H2O2, was markedly increased under Put or Spd treatments, but strongly inhibited by Spm and was not modified by SNP. These results suggest that a complex interaction exists among polyamines, ROS and NO in the inhibition of root growth, where PAs are not only a source of ROS, but could be modulating the antioxidant system, thus directly modifying O2.- or H2O2 levels.