Activating defense responses and reducing postharvest blue mold decay caused by Penicillium expansum in peach fruit by yeast saccharide

The effects of a saccharide fraction prepared from yeast cell walls on defense responses and blue mold decay caused by Penicillium expansum of peach fruit during postharvest storage were evaluated. Treatment of the fruit with 0.5 mg/L yeast saccharide (YS) significantly reduced decay incidence. The total phenolic contents and the activities of chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase, and peroxidases in fruit pretreated with YS were significantly higher than those of the control fruit, indicating that YS treatment activated defense responses of the fruit. Moreover, YS triggered a marked increase in endogenous nitric oxide (NO) levels of the fruit during postharvest storage. The NO specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide not only abolished a YS-triggered NO burst but also inhibited YS-induced decay alleviation and defense responses of the fruit. Together, the data showed that YS may have potential application for reducing decay of peach fruit during postharvest storage. Furthermore, the results demonstrated that the YS-induced decay alleviation and defense responses of peach fruit were dependent on endogenous NO generation.

► Yeast saccharide (YS) alleviates postharvest decay of peach fruit.
► YS induces phenolic synthesis and chitinase, β-1,3-glucanase, PAL and POD activity.
► YS triggers a marked increase in NO levels in peach fruit.
► The NO scavenger diminishes YS-induced decay alleviation and defense responses.
► YS activates defense responses and reduces fruit decay dependent on endogenous NO.