Grapevine rootstocks can be a source of infection with non-regulated viruses

Abstract

Grapevine can be infected by several viruses and viroids, the presence of which can lead to yield losses and vineyard decline. Our previous survey of vineyards in Hungary suggested that viral infection originates from infected propagation material. To investigate whether rootstocks can be a source of virus infections, we surveyed seventeen rootstock vineyards and two rootstock collections in Hungary to determine the virome by high-throughput sequencing of small RNAs. The presence of the viruses was also tested by RT-PCR. The results showed that viruses whose presence is routinely checked were almost absent in rootstock vineyards but were present in rootstock genotype collections. Moreover, first the time in Hungary, we detected the presence of Australian grapevine viroid in the rootstock genotype collection at Pecs. In contrast, viruses that are not regulated or not routinely tested, namely, grapevine rupestris stempitting-associated virus, grapevine Syrah virus-1 and grapevine Pinot gris virus, were detected in almost all locations in most of the varieties. The presence and absence of infected rootstock genotypes in the same vineyard together with phylogenetic analysis suggested that viral infections originated from infected propagation material. Moreover, we found the symptomatic variant of grapevine Pinot gris virus in several rootstock vineyards without symptoms, suggesting the possibility for leaf mottling and deformation disease symptoms to manifest on susceptible cultivars following grafting onto these rootstocks.

HTS-Based Monitoring of the Efficiency of Somatic Embryogenesis and Meristem Cultures Used for Virus Elimination in Grapevine

“…In contrast, and in agreement with our previous observations, small RNA HTS failed to detect GRSPaV infection [ 26 , 27 ]; we observed the same contradictions for GVT. GVT is a close relative of GRSPaV, and we hypothesize that its detection could have failed because of (i) its high variability or (ii) its low level of produced small RNA.…”

High-Throughput Sequencing of Small RNAs for Diagnostics of Grapevine Viruses and Viroids in Russia

“…However, as a result of mapping the unique and redundant reads ('with Vitis') of each of the libraries to the reference genome GVT NC_035203, we were able to find 7787 non-redundant reads in the Lib-03_S20 library, one non-redundant read in the Lib-04_S21 library, and two redundant read in the Lib-05_S22 library (Supplementary Table S6). In a number of earlier studies devoted to the analysis of the grapevine virome, GVT was not detected in sRNA libraries [22,[38][39][40]. However, a reanalysis of the results obtained in 2018 and 2020 [21,22] by bioinformatics and molecular methods confirmed the presence of the virus in Hungarian vineyards [41].…”

“…In a number of earlier studies devoted to the analysis of the grapevine virome, GVT was not detected in sRNA libraries [22,[38][39][40]. However, a reanalysis of the results obtained in 2018 and 2020 [21,22] by bioinformatics and molecular methods confirmed the presence of the virus in Hungarian vineyards [41].…”

“…It is believed that by using sRNA HTS, it is difficult to detect viruses that are constantly present in a plant, and it is not always possible to assemble complete genomes of new viruses [15]. However, despite existing difficulties, this approach has made it possible to establish sequences of five new viruses, including Grapevine Pinot Gris virus [16], Grapevine Roditis leaf-discoloration-associated virus [17], Grapevine vein clearing virus [18] and others [19,20], and examine the viromes of vineyards [16,[21][22][23].…”

Survey of five major grapevine viruses infecting Blatina and Žilavka cultivars in Bosnia and Herzegovina

“…Furthermore, the introduction of next-generation sequencing techniques would be highly recommended for the identification of all the foreign RNA and DNA sequences present in grapevine samples, enabling the detection of new viruses, of agronomically important viruses, and of latent viruses present at low titers. Full virome analyses might also contribute to modify the BiH phytopathological legislation and introduce new candidate target viruses in future surveys of grapevine propagation material [ 87 , 88 ]. All these measures will help to preserve the six century-old autochthonous cultivars used mainly for the production of ‘high-quality’ wines in this country.…”