Impacts of Grapevine Leafroll Disease on Fruit Yield and Grape and Wine Chemistry in a Wine Grape (Vitis vinifera L.) Cultivar.

Hernâni Gerós,Olufemi J Alabi,Rayapati A Naidu,Richard C Larsen,James F Harbertson,Thomas Henick-Kling,L Federico Casassa,Linga R Gutha

doi:10.1371/journal.pone.0149666

Hernâni Gerós, Olufemi J Alabi + Show 6 more

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https://doi.org/10.1371/journal.pone.0149666

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Journal: PloS one	Publication Date: Feb 26, 2016
Citations: 65	License type: CC BY 4.0

Affiliation: Washington State University

Abstract

Grapevine leafroll disease (GLD) is an economically important virus disease affecting wine grapes (Vitis vinifera L.), but little is known about its effect on wine chemistry and sensory composition of wines. In this study, impacts of GLD on fruit yield, berry quality and wine chemistry and sensory features were investigated in a red wine grape cultivar planted in a commercial vineyard. Own-rooted Merlot vines showing GLD symptoms and tested positive for Grapevine leafroll-associated virus 3 and adjacent non-symptomatic vines that tested negative for the virus were compared during three consecutive seasons. Number and total weight of clusters per vine were significantly less in symptomatic relative to non-symptomatic vines. In contrast to previous studies, a time-course analysis of juice from grapes harvested at different stages of berry development from symptomatic and non-symptomatic vines indicated more prominent negative impacts of GLD on total soluble solids (TSS) and berry skin anthocyanins than in juice pH and titratable acidity. Differences in TSS between grapes of symptomatic and non-symptomatic vines were more pronounced after the onset of véraison, with significantly lower concentrations of TSS in grapes from symptomatic vines throughout berry ripening until harvest. Wines made from grapes of GLD-affected vines had significantly lower alcohol, polymeric pigments, and anthocyanins compared to corresponding wines from grapes of non-symptomatic vines. Sensory descriptive analysis of 2010 wines indicated significant differences in color, aroma and astringency between wines made from grapes harvested from GLD-affected and unaffected vines. The impacts of GLD on yield and fruit and wine quality traits were variable between the seasons, with greater impacts observed during a cooler season, suggesting the influence of host plant × environment interactions on overall impacts of the disease.

Highlights

Viruses produce a wide range of symptoms in susceptible plants, modulate host metabolic pathways and cause significant losses to crop yield and quality of produce [1,2,3,4]
Grapevines with and without Grapevine leafroll disease (GLD) symptoms (Fig 1) were retested by RT-PCR during each season to ensure that vines with symptoms are positive for GLRaV-3 and those without symptoms are negative for the virus
In the 2009 and 2010 seasons, twelve vines with GLD symptoms and tested positive for GLRaV-3 and equal number of non-symptomatic vines adjacent to symptomatic vines and tested negative for the virus were selected for collecting data on fruit yield and weight of cane pruning

Summary

Introduction

Viruses produce a wide range of symptoms in susceptible plants, modulate host metabolic pathways and cause significant losses to crop yield and quality of produce [1,2,3,4]. The extent of negative impacts of viruses, depends on specific virus-host combinations, virulence of the virus, cultivar susceptibility and plant age at which infection has occurred. A great deal of knowledge on compatible plant–virus interactions and impacts of virus infections on plant life-history traits are available from annual plants [5]. Studies on the consequences of virus infections in perennial plants are very limited. The dynamics of compatible host-virus interactions in perennial plants may be more complex and subject to an array of environmental variables and developmental cues across consecutive seasons compared to annual plants [6]

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