Salinity-induced decrease in NADPH oxidase activity in the maize leaf blade elongation zone

ANDRES ALBERTO RODRIGUEZ; HERNAN RAMIRO LASCANO; BUSTOS, D; EDITH TALEISNIK

JOURNAL OF PLANT PHYSIOLOGY

ELSEVIER GmbH

Año: 2007 vol. 164 p. 223 - 230

0176-1617

We reported previously that salinity-induced elongation constraints in the expansionzone of maize leaves are associated with reduced reactive oxygen species (ROS)production and could be alleviated by the addition of ROS. The NaCl effect was saltspecificand not osmotic. This paper explores the causes for such reduction. Thedecrease in ROS levels under salinity was not accompanied by increases in solubleapoplastic antioxidant activities such as superoxide dismutase, peroxidases andascorbate. In experimental systems devoid of cell walls (protoplasts and membranefractions) superoxide anion (·O2-) production was inhibited by 50 and 100mM NaCl,50 mM DPI, 10mM EGTA, and 5mM verapamil, a Ca2+ channel inhibitor. Inhibitoryeffects of NaCl and reduced Ca2+ supply were also observed in in gel assessment of·O2--generating activity. The main activity band excised from the ND-PAGE wasrecognized by an antibody against the C-terminal portion of the tomato gp91phoxhomolog. These results indicate the ·O2--generating activity negatively affected byNaCl was compatible with that of plasma membrane NADPH oxidase.& 2006 Elsevier GmbH. All rights reserved.