Predominance and Diversity of GLRaV-3 in Native Vines of Mediterranean Croatia.

Katarina Hančević,Silvija Černi,Pasquale Saldarelli,Mate Čarija,Ana Mucalo,Goran Zdunić,Tomislav Radić

doi:10.3390/plants10010017

Abstract

Sixteen grapevine cultivars from Mediterranean Croatia were surveyed for the presence of 10 of the most economically important grapevine viruses. The presence of Grapevine fanleaf virus (GFLV), Arabis mosaic virus (ArMV), Grapevine leafroll associated virus-1, -2, and -3 (GLRaV-1; GLRaV-2 and GLRaV-3), Grapevine virus A (GVA) and B (GVB), Grapevine fleck virus (GFkV), Grapevine rupestris stem pitting associated virus (GRSPaV), and Grapevine Pinot gris virus (GPGV) were tested by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). All 71 analyzed clones were positive for the presence of one or more viruses. The most abundant one, detected in almost 95% of samples was GLRaV-3. In most of cases it was reported in mixed infections with GVA, GRSPaV, and GPGV. Virus genomes of GLRaV-3 infected vines were further characterized molecularly in order to determine their genetic diversity. Different genomic variants of heat shock 70 protein homologue (HSP70h) were identified by single-strand conformation polymorphism (SSCP) and sequenced. Sequence analysis confirmed their clustering into phylogenetic group I and/or phylogenetic group II. This study emphasizes the wide virus heterogenicity in Mediterranean vines and the predominant presence of GLRaV-3 phylogenetic groups I and II, either individually or in combination.

Highlights

A high prevalence was recorded for Grapevine rupestris stem pitting associated virus (GRSPaV) (81.69%), Grapevine virus A (GVA) (80.28%) and Grapevine Pinot gris virus (GPGV) (61.97%), while prevalence of GLRaV-1, Grapevine fleck virus (GFkV), GVB, Grapevine fanleaf virus (GFLV), GLRaV-2, and especially Arabis mosaic virus (ArMV) were much lower (Figure 1)
The collection was established during the long-term identification and conservation program of old native grapevine varieties, encompassing all main autochthonous cultivars from Mediterranean Croatia collected along the coastal area, more than 350 km long
Fresh tissue was grinded in liquid nitrogen and proceed further for the screening of Grapevine fanleaf virus (GFKV), Arabis mosaic virus (ArMV), Grapevine leafroll associated virus-1, -2, and -3 (GLRaV-1; GLRaV-2, and Grapevine leafroll-associated virus 3 (GLRaV-3)), Grapevine virus A, (GVA) and B (GVB), Grapevine fleck virus (GFkV), Grapevine rupestris stem pitting associated virus (GRSPaV) and Grapevine Pinot gris virus (GPGV)

Summary

Introduction

In comparison to other cultivated crops, grapevines are amongst those infected with the greatest number of viruses. The most damaging and widespread grapevine viruses are those causing four major diseases: leafroll disease complex, rugose wood complex, infectious degeneration and decline, and fleck [1]. Grapevine leafroll-associated virus 3 (GLRaV-3), the main causal agent of leafroll disease, is one of the most important virus pathogens worldwide. It is a positive-stranded RNA virus, belonging to the genus Ampelovirus, family Closteroviridae [2]. While symptomless and unrecognized in rootstocks, contributing to its spread, important economic losses are reported in Vitis vinifera infected with GLRaV-3 [3]. GLRaV-3 pathogenicity is evident via leaf downward rolling typical symptoms in red vine variety, delayed ripening, reduced berry sugar content, and a spectrum of disturbed physiological processes, mainly photosynthesis and those related to carbohydrate metabolisms [4]

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