Multiple Infections with Viruses of the Family Tymoviridae in Czech Grapevines.

This study focused on the viruses of the Tymoviridae family that infect grapevines in the Czech Republic. Complete sequences of GFkV (grapevine fleck virus) and GRGV (grapevine red globe virus) from the genus Maculavirus and GRVFV (grapevine rupestris vein feathering virus) and GSyV-1 (grapevine Syrah virus 1) from the genus Marafivirus were obtained using high-throughput sequencing of small RNAs and total RNAs. Mixed infections with these viruses were observed, as well as several variants of these viruses in the same plant. Phylogenetic analysis showed the position of the newly obtained virus isolates within the Tymoviridae family. Recombinant analysis provided evidence of single and multiple intraspecific recombinations in GRGV, GSyV-1, and GRVFV. Additionally, GAMaV, a grapevine virus from the genus Marafivirus, was reported for the first time in the Czech Republic.

Characterization of Prunus Necrotic Ringspot Virus and Cherry Virus A Infecting Myrobalan Rootstock.

Prunus necrotic ringspot virus (PNRSV) and cherry virus A (CVA) are two viruses that mainly infect plants of the genus Prunus. Full-length sequences of these two viruses, collected in the Czech Republic from Prunus cerasifera plants, were obtained via HTS sequencing. Phylogenetic analyses based on the NJ method and Splitstree tools showed that the Czech PNRSV isolate (ON088600-ON088602) is a divergent isolate from other molecular groups, sharing less than 97% pairwise nucleotide identity with members of other groups. The Czech CVA isolate (ON088603) belonged to molecular subgroup III-2, clustered with isolates from non-cherry hosts, and shared the highest pairwise nucleotide identity (99.7%) with an isolate of Australian origin.

High-throughput small RNA sequencing for evaluation of grapevine sanitation efficacy.

This study describes the application of high-throughput sequencing of small RNA analysis of the efficacy of using Ribavirin to eliminate Grapevine leafroll-associated virus 1, Grapevine fleck virus and Grapevine rupestris stem pitting-associated virus from Vitis vinifera cv. Riesling. The original plant used for sanitation by Ribavirin treatment was one naturally infected with all the viruses mentioned above as confirmed by RT-PCR. A tissue cultures of the plant were established and plantlets obtained were sanitized using Ribavirin. Three years after sanitation, a small RNA sequencing method for virus detection, targeting 21, 22 and 24 nt-long viral small RNAs (vsRNAs), was used to analyze both the mother plant and the sanitized plants. The results showed that the mother plant was infected by the three mentioned viruses and additionally by two viroids - Hop stunt viroid and Grapevine yellow speckle viroid 1. After Ribavirin treatment, the plants contained only the two viroids, with the complete elimination of all the viruses previously present.

Characterisation of a novel virus infecting orchids of the genus Pleione.

Plants of the genus Pleione, originating from hobby growers in the Netherlands and in the Czech Republic, were conspicuous for viral infection, showing symptoms of leaf mosaic or flower breaking. Using Sanger and high throughput sequencing, the full genome sequence of a novel potyvirus was obtained from sequencing data. The genome sequence was annotated and compared to the genome of other potyviruses. The virus was experimentally transmitted by aphids into Pleione and Chenopodium quinoa plants. The name Pleione flower breaking virus (PlFBV) was suggested for the new virus. The presence of the virus was confirmed using RT-PCR, with newly designed primers targeting this new species. The incidence of the virus was contrasted between both countries and might have been influenced by the growth conditions and the exposure of the plants to aphids.

Comprehensive Virus Detection Using Next Generation Sequencing in Grapevine Vascular Tissues of Plants Obtained from the Wine Regions of Bohemia and Moravia (Czech Republic).

Comprehensive next generation sequencing virus detection was used to detect the whole spectrum of viruses and viroids in selected grapevines from the Czech Republic. The novel NGS approach was based on sequencing libraries of small RNA isolated from grapevine vascular tissues. Eight previously partially-characterized grapevines of diverse varieties were selected and subjected to analysis: Chardonnay, Laurot, Guzal Kara, and rootstock Kober 125AA from the Moravia wine-producing region; plus Müller-Thurgau and Pinot Noir from the Bohemia wine-producing region, both in the Czech Republic. Using next generation sequencing of small RNA, the presence of 8 viruses and 2 viroids were detected in a set of eight grapevines; therefore, confirming the high effectiveness of the technique in plant virology and producing results supporting previous data on multiple infected grapevines in Czech vineyards. Among the pathogens detected, the Grapevine rupestris vein feathering virus and Grapevine yellow speckle viroid 1 were recorded in the Czech Republic for the first time.