Induction of resistance in apple fruit inoculated with antagonistic Candida membranifaciens isolates and Botrytis mali

The biocontrol activity of two isolates of Candida membranifaciens against grey mold of apple fruit caused by Botrytis mali and their ability to induce biochemical defense responses in apple tissue were investigated. Apple fruit (Malus domestica) wounds were inoculated with ۵۰ µl yeast suspension (۱ × ۱۰۷ CFU/ml) of C. membranifaciens followed ۴ h later by ۲۰ µl of conidial suspension of B. mali (۱ × ۱۰۵ conidia/ml). The apples were then incubated at ۲۰ ºC for ۸ days. Lesion diameter sizes were measured ۴ and ۸ days after pathogen inoculation. In addition to controlling grey mold, these two isolates of C. membranifaciens caused increases in peroxidase and β-۱, ۳-glucanase activities. These isolates also caused inhibition in catalase activity. The accumulation of phenolic compounds was increased in apple fruit treated with antagonists and inoculated with B. mali and reached its highest level ۶ days after treatment. The ability of C. membranifaciens to affect H۲O۲-metobolizing enzymes and increase levels of β-۱, ۳-glucanase activity and phenolic compounds may be some of mechanisms responsible for its biocontrol activity.

Keywords:

phenolic compounds , Catalase , Peroxidase , β-۱ , ۳-glucanase