Nitric oxide synthase activity is required for development of functional nodules in soybean

• DOI: 10.1016/j.jplph.2010.06.019
• Publication Date: 2010-08-15T08:30:31Z
• Authors: Jacobus Leach; Marshall Keyster; Morné Du Plessis; Ndiko Ludidi
• Keywords: 0106 biological sciences; Glycine max; Nitrogen Fixation; Nitric Oxide Synthase; Root Nodules, Plant; 01 natural sciences

The effects of a nitric oxide synthase inhibitor (N(ω)-nitro-L-arginine) on soybean growth parameters and nodule functioning were investigated, along with soybean nodule cell viability and cysteine endopeptidase activity. N(ω)-nitro-L-arginine reduced soybean growth parameters, inhibited nodule nitrogenase activity, and caused a decrease in nodule cell viability. The negative effects of N(ω)-nitro-L-arginine were reversed by the nitric oxide donor 2,2'-(hydroxynitrosohydrazono)bis-ethanimine. Cysteine endopeptidase activity was higher in plants treated with N(ω)-nitro-L-arginine than untreated plants (controls), but decreased to levels similar to the controls when plants were exposed to a combination of N(ω)-nitro-L-arginine and 2,2'-(hydroxynitrosohydrazono)bis-ethanimine. These results suggest that nitric oxide, resulting from nitric oxide synthase activity, is required for development of functional soybean nodules.