Grapevine Pinot Gris Virus Isolates Research Articles

DETECTION OF GRAPEVINE PINOT GRIS VIRUS IN CERTIFIED GRAPEVINE STOCKS IN MORAVIA, CZECH REPUBLIC

Twenty one grapevine mother plants used by nurseries for propagation in South Moravia, Czech Republic, were tested for the presence of Grapevine Pinot gris virus (GPGV) and other viruses by simplex and multiplex RT-PCR. GPGV was found in all vines tested and Grapevine virus A, Grapevine fanleaf virus and Grapevine fleck virus were detected only in some of them. Part of the movement and coat protein coding regions of 21 GPGV isolates was sequenced. Phylogenetic analysis revealed that south Moravian GPGV isolates grouped with isolates from other regions and countries. This study provides the first comprehensive survey of the GPGV occurrence in South Moravia.

Grapevine Pinot gris virus seems to have recently been introduced to vineyards in Veneto, Italy.

Grapevine Pinot gris virus (GPGV), a member of the genus Trichovirus in the family Betaflexiviridae, was recently discovered in Italy and subsequently in other European countries and in Korea. In this study, we assessed the occurrence of GPGV in 441 samples from Western and Eastern Europe collected over the period 2002-2014. The results suggest that the virus had recently appeared in the Veneto region (Northeast Italy) and had been present in some Eastern European countries for at least 10 years. The molecular characterization of the 5'-terminal genomic region of several GPGV isolates from Italy and other European countries showed low polymorphism, with a maximum nucleotide sequence divergence of 3.2%.

Genetic Variability of Grapevine Pinot gris virus and Its Association with Grapevine Leaf Mottling and Deformation.

The role of Grapevine Pinot gris virus (GPGV) in the etiology of grapevine leaf mottling and deformation was investigated by biological and molecular assays. A survey on different cultivars from the Trentino Region in Italy showed a widespread distribution of GPGV, which was associated with symptomatic (79%) but also with symptomless (21%) vines. Symptomatic and GPGV-infected 'Pinot gris' vines induced symptoms on grafted vines of healthy Pinot gris or 'Traminer', whereas GPGV-infected but symptomless vines did not. High-throughput sequencing of small RNA (sRNA) populations of two infected Pinot gris accessions confirmed the existence of nearly overlapping viromes in vines with or without symptoms but phylogenetic analyses of the genomes of seven GPGV isolates from Italy and the Czech and Slovak Republics clearly differentiated those infecting symptomatic vines. The involvement of Grapevine rupestris vein feathering virus (GRVFV) in the disease, which was only infecting the symptomatic vine, was ruled out by reverse-transcription polymerase chain reaction studies. Maximum likelihood and Bayesian phylogenetic analysis of two GPGV genomic regions, encompassing part of the movement protein (MP) and coat protein gene sequences and the RNA-dependent RNA polymerase domain of the replicase gene, showed that isolates from symptomatic vines form a lineage distinct from that of symptomless vines. Moreover, the presence or lack of the MP stop codon identified in viral isolates from symptomatic or symptomless vines, respectively, is likely responsible for an MP six amino acids longer in symptomless isolates.

First Report of Grapevine Pinot gris virus (GPGV) in grapevine in France

Grapevine Pinot gris virus (GPGV), belonging to the genus Trichovirus of the family Betaflexiviridae, was first identified by siRNA sequencing in northern Italy in 2012, in the grapevine varieties Pinot gris, Traminer, and Pinot Noir, which exhibited mottling and leaf deformation (1), and in asymptomatic vines, with a lower frequency. Since 2012, this virus has also been reported in South Korea, Slovenia, Greece (3), Czech Republic (2), Slovakia (2), and southern Italy (4). In 2014, GPGV was identified by Illumina sequencing of total RNAs extracted from leaves of the Merlot variety (Vitis vinifera) grafted onto Gravesac rootstock originated from a vineyard in the Bordeaux region of France. This Merlot plant exhibited fanleaf-like degeneration symptoms associated with Tomato black ring virus (TBRV) infection. Cuttings were collected in 2010 and maintained thereafter in a greenhouse. The full-length genome was assembled either de novo or by mapping of the Illumina reads on a reference GPGV genome (GenBank FR877530) using the CLC Genomics workbench software (CLC Bio, Qiagen, USA). The French GPGV isolate "Mer" (7,223 nucleotides, GenBank KM491305) is closely related to other European GPGV sequences; it exhibits 95.4% nucleotide identity with the reference Italian isolate (NC_015782) and 98 to 98.3% identity with Slovak isolates (KF134123 to KF134125). The higher divergence between French and Italian GPGV isolates was mainly due to differences in the 5' extremity of the genome, as already shown with the Slovak GPGV isolates. RNA extracted from phloem scrapings of 19 cv. Merlot vines from the same plot collected in 2014 were analyzed by RT-PCR using the specific primer pair Pg-Mer-F1 (5'-GGAGTTGCCTTCGTTTACGA-3') and Pg-Mer-R1 (5'-GTACTTGATTCGCCTC GCTCA-3'), designed on the basis of alignments of all available GPGV sequences from GenBank. The resulting amplicon of 770 bp corresponded to a fragment of the putative movement protein (MP) gene. Seven (35%) of the tested plants gave a strong positive amplification. Three RT-PCR products were directly sequenced and showed 99.3 to 99.5% identity within the MP gene of the GPGV-Mer isolate. Given the mixed viral infection status of the vines found infected by GPGV, it was not possible to associate a specific symptomatology with the presence of GPGV. Furthermore, similar RT-PCR tests were also performed on RNA extracts prepared from two plants of cv. Carignan that originated from a French grapevine collection, exhibiting fanleaf-like symptoms without any nepovirus detection. These samples similarly gave a strong positive amplification. The sequences obtained from the two Carignan vines showed 98.4 and 97.8% identity with the GPGV-Mer isolate. To our knowledge, this is the first report of GPGV in France. GPGV has been discovered in white and red berry cultivars, suggesting that its prevalence could be important in European vineyards (2). Further large-scale studies will be essential to determine the world prevalence of GPGV and to evaluate its potential effects on yield and on wine quality, as well as to shed light on GPGV epidemiology. Of particular concern is whether, like the other grapevine-infecting Trichovirus, Grapevine berry inner necrosis virus (GPGV) can be transmitted by the eryophid mite Colomerus vitis.

Molecular characterization of divergent grapevine Pinot gris virus isolates and their detection in Slovak and Czech grapevines

Analysis of complete genome sequences of three Slovak isolates of grapevine Pinot gris virus (GPGV) showed their low heterogeneity (reaching 1.7 %) and a close relationship to the Italian NC_015782 isolate (4.2-4.5 % divergence). Comparison of Slovak and Italian isolates revealed an unusual accumulation of 21 indel mutations in ORF1, resulting in a localized high divergence in the encoded amino acid sequences. An elevated divergence in the 5' extremity of the GPGV genomes is suggestive of a recombination between Slovak isolates and grapevine berry inner necrosis virus. RT-PCR allowed the frequent detection of closely related GPGV isolates in grapevines from Slovakia and the Czech Republic.