Modifications of Grapevine Berry Composition Induced by Main Viral and Fungal Pathogens in a Climate Change Scenario.

Markus Rienth,Simone Diego Castellarin,Philippe Darriet,Claudio Bonghi,Crista A Burbidge,Franco Famiani,Crystal Sweetman,Nicolas Vigneron,Robert P Walker

doi:10.3389/fpls.2021.717223

Abstract

The grapevine is subject to high number of fungal and viral diseases, which are responsible for important economic losses in the global wine sector every year. These pathogens deteriorate grapevine berry quality either directly via the modulation of fruit metabolic pathways and the production of endogenous compounds associated with bad taste and/or flavor, or indirectly via their impact on vine physiology. The most common and devastating fungal diseases in viticulture are gray mold, downy mildew (DM), and powdery mildew (PM), caused, respectively by Botrytis cinerea, Plasmopara viticola, and Erysiphe necator. Whereas B. cinerea mainly infects and deteriorates the ripening fruit directly, deteriorations by DM and PM are mostly indirect via a reduction of photosynthetic leaf area. Nevertheless, mildews can also infect berries at certain developmental stages and directly alter fruit quality via the biosynthesis of unpleasant flavor compounds that impair ultimate wine quality. The grapevine is furthermore host of a wide range of viruses that reduce vine longevity, productivity and berry quality in different ways. The most widespread virus-related diseases, that are known nowadays, are Grapevine Leafroll Disease (GLRD), Grapevine Fanleaf Disease (GFLD), and the more recently characterized grapevine red blotch disease (GRBD). Future climatic conditions are creating a more favorable environment for the proliferation of most virus-insect vectors, so the spread of virus-related diseases is expected to increase in most wine-growing regions. However, the impact of climate change on the evolution of fungal disease pressure will be variable and depending on region and pathogen, with mildews remaining certainly the major phytosanitary threat in most regions because their development rate is to a large extent temperature-driven. This paper aims to provide a review of published literature on most important grapevine fungal and viral pathogens and their impact on grape berry physiology and quality. Our overview of the published literature highlights gaps in our understanding of plant-pathogen interactions, which are valuable for conceiving future research programs dealing with the different pathogens and their impacts on grapevine berry quality and metabolism.

Highlights

The European grapevine Vitis vinifera L., by far the main Vitis species used for wine production in the world, is host of a multitude of biotic adveristies from insects and fungi to viruses and bacteria
The first part of this review aims to summarize the most important and recent studies dealing with the effects of gray mold, PM, and downy mildew (DM) on berry quality and metabolism
We review the literature describing the effects on berry physiology of the most important virus-related diseases, such as grapevine fanleaf, grapevine leafroll, and red blotch disease

Summary

Introduction

The European grapevine Vitis vinifera L., by far the main Vitis species used for wine production in the world, is host of a multitude of biotic adveristies from insects and fungi to viruses and bacteria. Downy and powdery mildew (DM and PM) are the major fungal pathogens in most wine-growing regions worldwide Because these two pathogens were accidentally imported into Europe from North America rather recently, at the end of the 19th century, their host, the European grapevine, did not co-evolve with them and does not possess natural resistances against them. The predicted increase in temperature caused by global warming is already leading to advances of the development of the grape berry moth whose larvae feed on ripening grape berries, thereby providing “entrygates” for B. cinerea infection (Reineke and Thiéry, 2016; Santos et al, 2020) This could result in increasing berry mold infections if pest management strategies are not adapted. A better understanding of pathogen-host interactions is of upmost importance for elaborating efficient disease-management strategies in order to guarantee high quality and sustainable wine production in an evolving environment

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