Accumulation of phenolic compounds in apple in response to infection by the scab pathogen, Venturia inaequalis

The research dealt with phenolics in healthy versus scab infected apple leaves and fruits. The leaf samples were picked in the period from May to September and the fruit samples at technological maturity. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolics at the infected sites, especially in the boundary tissue. Tissue infected with Venturia inaequalis showed in comparison to the healthy tissue up to 7.6 times more hydroxycinnamic acids, up to 2.6 times more flavan-3-ols and up to 2.9 times higher values of flavanols. The content level of total phenolics in the infected tissue was 1.3–2.4 times higher than in the healthy leaves and fruit.