Grapevine Leafroll-Associated Virus 3 Genotype Influences Foliar Symptom Development in New Zealand Vineyards

Kar Mun Chooi; Vaughn A Bell; Arnaud G Blouin; Daniel Cohen; Dion Mundy; Warwick Henshall; Robin M MacDiarmid

doi:10.3390/v14071348

Grapevine Leafroll-Associated Virus 3 Genotype Influences Foliar Symptom Development in New Zealand Vineyards

Viruses. 2022 Jun 21;14(7):1348. doi: 10.3390/v14071348.

Authors

Kar Mun Chooi¹, Vaughn A Bell², Arnaud G Blouin³, Daniel Cohen¹, Dion Mundy⁴, Warwick Henshall¹, Robin M MacDiarmid^{1

5}

Affiliations

¹ The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland 1142, New Zealand.
² The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 1401, Havelock North 4157, New Zealand.
³ Virology-Phytoplasmology Laboratory, Agroscope, 1260 Nyon, Switzerland.
⁴ The New Zealand Institute for Plant and Food Research Limited (PFR), P.O. Box 845, Blenheim 7240, New Zealand.
⁵ School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.

Abstract

Grapevine leafroll disease (GLD) constrains wine production worldwide. In New Zealand, the main causal agent of GLD is grapevine leafroll-associated virus 3 (GLRaV-3). To control GLD, an integrated management program is used and includes removing (roguing) GLRaV-3-infected vines from the vineyard. The classical foliar symptoms from virus-infected red-berry cultivars are leaves with dark red intervein, green veins, and downward rolling of margins. Growers use these phenotypic cues to undertake visual symptom identification (VSI) for GLD. However, the influence of the known large genetic variation among GLRaV-3 isolates on the foliar symptoms from different grapevine cultivars remains undescribed, especially in cool-climate growing environments, such as New Zealand. Over three vintages (2015, 2016, and 2017), VSI for GLD was undertaken at three field sites in New Zealand (Auckland, Hawke’s Bay, and Marlborough), each including four cultivars (Merlot, Pinot noir, Sauvignon blanc, and Pinot gris) infected with three GLRaV-3 genotypes (Groups I, VI, and X) or GLRaV-3-uninfected control plants. Throughout this study, no visual symptoms were observed on white-berry cultivars infected with GLRaV-3. For red-berry cultivars, the greatest variability in observed foliar symptoms among regional study sites, cultivars, and GLRaV-3 genotypes was observed early in the growing season. In particular, Group X had significantly delayed symptom expression across all three sites compared with Groups I and VI. As the newly infected, young vines matured in years 2 and 3, the GLRaV-3 genotype, cultivar, region, and environmental conditions had minimal influence on the accuracy of VSI, with consistently high (>95%) within-vintage identification by the end of each vintage. The results from this study strongly support the use of VSI for the GLD management of red-berry cultivar grapevines, Merlot and Pinot noir, as a reliable and cost-effective tool against GLD.

Keywords: grapevine leafroll disease; grapevine leafroll-associated virus 3; host–virus interaction; visual symptoms identification.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Closteroviridae
Farms
Genotype
New Zealand
Plant Diseases
Vitis*

Supplementary concepts

Grapevine leafroll-associated virus 3

Grants and funding

K.M.C. was supported by postdoctoral fellowships from New Zealand Winegrowers and the Agricultural and Marketing Research and Development Trust (AGMARDT). The resources were funded by AGMARDT and Ministry of Business, Innovation and Employment (MBIE)—Strategic Science Investment Funding.