Abstract:
Infection of grapevines with the grey mold pathogen Botrytis cinerea results in severe problems for winemakers worldwide. Browning of wine is caused by the laccase-mediated oxidation of polyphenols. In the last decades, Botrytis management has become increasingly difficult due to the rising number of resistances and the genetic variety of Botrytis strains. During the search for sustainable fungicides, polyphenols showed great potential to inhibit fungal growth. The present study revealed two important aspects regarding the effects of grape-specific polyphenols and their polymerized oxidation products on Botrytis wild strains. On the one hand, laccase-mediated oxidized polyphenols, which resemble the products found in infected grapes, showed the same potential for inhibition of growth and laccase activity, but differed from their native forms. On the other hand, the impact of phenolic compounds on mycelial growth is not correlated to the effect on laccase activity. Instead, mycelial growth and relative specific laccase activity appear to be modulated independently. All phenolic compounds showed not only inhibitory but also inductive effects on fungal growth and/or laccase activity, an observation which is reported for the first time. The simultaneous inhibition of growth and laccase activity demonstrated may serve as a basis for the development of a natural botryticide. Yet, the results showed considerable differences between genetically distinguishable strains, impeding the use of a specific phenolic compound against the genetic variety of wild strains. The present findings might have important implications for future understanding of Botrytis cinerea infections and sustainable Botrytis management including the role of polyphenols.
摘要:
用灰霉病菌灰葡萄孢感染葡萄会给全世界的酿酒师带来严重的问题。葡萄酒的褐变是由漆酶介导的多酚氧化引起的。在过去的几十年里,由于抗性数量的增加和葡萄孢菌株的遗传多样性,葡萄孢的管理变得越来越困难。在寻找可持续杀菌剂的过程中,多酚显示出抑制真菌生长的巨大潜力。本研究揭示了葡萄特异性多酚及其聚合氧化产物对葡萄孢属野生菌株的影响的两个重要方面。一方面,漆酶介导的氧化多酚,类似于在受感染的葡萄中发现的产品,显示出相同的抑制生长和漆酶活性的潜力,但与它们的原生形式不同。另一方面,酚类化合物对菌丝生长的影响与对漆酶活性的影响无关。相反,菌丝体生长和相对特异性漆酶活性似乎是独立调节的。所有酚类化合物不仅对真菌生长和/或漆酶活性具有抑制作用,而且具有诱导作用。首次报道的观察结果。所证明的同时抑制生长和漆酶活性可以作为开发天然杀葡萄剂的基础。然而,结果表明,遗传上可区分的菌株之间存在相当大的差异,阻碍使用特定的酚类化合物对抗野生菌株的遗传变种。目前的发现可能对未来了解灰葡萄孢菌感染和可持续的灰葡萄孢菌管理(包括多酚的作用)具有重要意义。