Resveratrol acts as a natural profungicide and induces self‐intoxication by a specific laccase

Abstract

Summary The grapevine (Vitis) secondary metabolite resveratrol is considered a phytoalexin, which protects the plant from Botrytis cinerea infection. Laccase activity displayed by the fungus is assumed to detoxify resveratrol and to facilitate colonization of grape. We initiated a functional molecular genetic analysis of B. cinerea laccases by characterizing laccase genes and evaluating the phenotype of targeted gene replacement mutants. Two different laccase genes from B. cinerea were characterized, Bclcc1 and Bclcc2. Only Bclcc2 was strongly expressed in liquid cultures in the presence of either resveratrol or tannins. This suggested that Bclcc2, but not Bclcc1, plays an active role in the oxidation of both resveratrol and tannins. Gene replacement mutants in the Bclcc1 and Bclcc2 gene were made to perform a functional analysis. Only Bclcc2 replacement mutants were incapable of converting both resveratrol and tannins. When grown on resveratrol, both the wild type and the Bclcc1 replacement mutant showed inhibited growth, whereas Bclcc2 replacement mutants were unaffected. Thus, contrary to the current theory, BcLCC2 does not detoxify resveratrol but, rather, converts it into compounds that are more toxic for the fungus itself. The Bclcc2 gene was expressed during infection of B. cinerea on a resveratrol‐producing host plant, but Bclcc2 replacement mutants were as virulent as the wild‐type strain on various hosts. The activation of a plant secondary metabolite by a pathogen introduces a new dimension to plant–pathogen interactions and the phytoalexin concept.

Developmental and metabolic plasticity of white-skinned grape berries in response to Botrytis cinerea during noble rot

“…The up-regulation of 40 genes coding for stilbene synthases together with the accumulation of stilbene glycosides in infected berries and botrytized wine verified the induction of stilbene biosynthesis during noble rot. Some stilbene dimers, in particular «-viniferin glycosides, have been reported to be more effective phytoalexins and to have stronger health-promoting effects than the monomeric stilbenoids (Schouten et al, 2002;Zghonda et al, 2012). The concomitant expression of the stilbene synthases directly correlated with the highly significant up-regulation of the VvMYB14 and VvMYB15 transcription factors, which are the master regulators of the stilbene pathway (Höll et al, 2013).…”

Laccases and Their Applications: A Patent Review

“…Laccase can also be used to synthesize various functional organic compounds including polymers with specific mechanical/electrical/optical properties, textile dyes, cosmetic pigments, flavor agents, and pesticides [110,[261][262][263].…”

Degradation of Food Manufacturing Wastes by a Fungal Isolate

“…Those values could be due to the presence of phenolic compounds in Mandel´s medium since this contains neopeptone. These results suggest the presence of mechanisms to degrade or transform phenolic compounds from the culture medium present on OMSW and GP cultures (Schouten et al, 2002). It is known that strain T1 secretes laccases that could be responsible for phenolic compounds oxidation (Espino et al, 2010;González-Fernández et al, 2014) (Fig.…”