Cholic acid changes defense response to oxidative stress in soybean induced by Aspergillus niger

Abstract

The oxidative stress and antioxidant systems in soybean leaves and roots infected with plant pathogen Aspergillus niger were studied following treatment with different concentrations of cholic acid. Several oxidative stress parameters were analyzed: production of superoxide (O-2 (center dot-)) and hydroxyl radicals ((OH)-O-center dot), lipid peroxidation (LP), and superoxide dismutase (SOD; EC 1.15.1.1) activity, as well as the content of reduced glutathione (GSH). Results showed that inoculation with A. niger led to the increase of O-2 (center dot-) production and GSH quantities in leaves and (OH)-O-center dot in roots. The highest activity of SOD occured in infected plants treated with cholic acid in concentrations of 40 and 60 mg L-1 which ultimately led to a decrease in O-2 (center dot-) production. Inoculation with Aspergillus in combination with elevated cholic acid concentrations also increased (OH)-O-center dot production which is correlated with increased LP. These results may support the idea of using cholic acid as an elicitor to trigger hypersensitive response in plant cells. Use of cholic acid may also actively contribute to soybean plants defense response against pathogen attack.