Markers for oxidative stress associated with soft rots in French beans (Phaseolus vulgaris) infected by Botrytis cinerea

The role of active oxygen species has been studied in spreading soft-rot le sions caused by the necrotrophic fungal pathogen Botrytis cinerea Pers.:Fr. in leaves of four genotypes of French bean (Phaseolus vulgaris L.). Large increases were observed for the aldehydic end-products of oxidative damage, malondialdehyde and 4-hydroxy-2-nonenal, as a result of infection in each of the genotypes studied. Similar increases were found in a stable free rad ical and g = 4.27 Fe(III) signals, but not Mn(II) signals, in electron para magnetic resonance spectra. These changes were accompanied by large decreas es in ascorbic acid levels, with changes in the antioxidant glutathione bei ng genotype dependent.