Abstract: Fuji apple fruit were artificially wounded and inoculated with Penicillium expansum (blue mold) at 24 h after being treated with a hyphal cell wall extract from Trichothecium roseum so as to evaluate the control of the extract on apple blue mold and to partially elucidate the underlying biochemical mechanism. The results showed that the treatment of the cell wall extract could effectively inhibit the development of inoculated P. expansum in apple wounds, and the best effect was observed at a concentration of 150 mg/mL, resulting in a reduction in disease severity of 29.5% after 5 d storage when compared with the control group. Further studies showed that the activity of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), 4-coumaryl coenzyme A ligase (4CL), cinnamic acid-4-hydroxylase (C4H) and cinnamyl alcohol dehydrogenase (CAD) was significantly increased by the treatment of the extract at 150 mg/mL (P < 0.05). At the same time, the contents of total phenols, flavonoids and lignin in fruit tissues were also increased. These findings suggested that the hyphal cell wall extract from T. roseum might enhance disease resistance by promoting the metabolism of phenylpropane, and increasing the activity of resistance-related enzyme activities and the accumulation of antifungal compounds.

Key words: Trichothecium roseum, hyphal cell wall extract, apple, blue mold, induced disease resistance