Grapevine downy mildew, caused by Plasmopara viticola, is a devastating disease worldwide. Most commercially important cultivars of the European grapevine are highly susceptible and therefore require the recurrent application of synthetic fungicides to control the disease, copper being the most frequently used. However, with European Union goals to lower their usage, there is a need to develop innovative and sustainable strategies. In this respect, seaweeds have proven to have great potential as phytosanitary agents, in addition to promoting plant growth and stress-tolerance. A greenhouse experiment was conducted to determine the effectiveness of an extract of the invasive Rugulopteryx okamurae (RO) as resistance inducer and fungicide against P. viticola. The molecular and metabolic responses of two Tempranillo clones (VN40, RJ43), together with the changes on plant physiology and soil microbiota were investigated after seaweed applications and post-pathogen inoculation. The extract preferentially induced Jasmonic acid (JA) related genes while inhibiting Salicylic acid (SA) responsive ones. In addition, in RO treated RJ43 plants SA pathway repression became stronger under P. viticola stress, and the antagonist relation between JA/SA pathways was corroborated. The later plants accumulated more piceid and had an increased activity of antioxidant enzymes. Moreover, RO slightly modified soil properties and soil fungal composition, the nematophagous biological control agent Harposporium being particularly high at seaweed treated RJ soils. Importantly, disease severity was reduced in RO treated plants indicating its ability to promote grapevine protection. All results suggest Ruguloperyx extract´s potential as palliative against P. viticola.

Andalusia is a Spanish region that is home to numerous minority varieties due to its diversity and territorial extension, offering the local viticulture the possibility of diversifying its wine production. The genotypic characterization of 98 specimens from six areas with a winemaking tradition in Andalusia was carried out between the years 2020 and 2022, by means of thirteen microsatellite markers, including the nine recommended by the OIV. A total of 33 different genotypes were obtained, 20 of which corresponded to profiles of already described varieties (11 of them are of 6 minority cultivars in Andalusia: ‘Rojal Tinto’, ‘Beba’, ‘Zurieles’, ‘Rome’, ‘Hebén’, ‘Mollar Cano’, ‘Listán Prieto’, ‘Listán del Condado’, ‘Jarrosuelto’, ‘Negra Dorada’, and ‘Mantúo de Pilas’), while the other 12 profiles did not match with previously identified varieties. These profiles were registered in the database of the IFAPA “Rancho de la Merced” Germplasm Bank. The eco-geographical groups of the new identified genotypes were determined through an analysis of genetic diversity. The presence of grapevine fanleaf virus, grapevine fleck virus, and grapevine leafroll-associated viruses was also determined due to the requirement of healthy clones of the new varieties for their potential interest to be authorized for cultivation in Spain.

Viticulture is highly dependent on phytochemicals to maintain good vineyard health. However, to reduce their accumulation in the environment, green regulations are driving the development of eco-friendly strategies. In this respect, seaweeds have proven to be one of the marine resources with the highest potential as plant protective agents, representing an environmentally-friendly alternative approach for sustainable wine production. The current work follows an interdisciplinary framework to evaluate the capacity of Ulva ohnoi and Rugulopteryx okamurae seaweeds to induce defense mechanisms in grapevine plants. To our knowledge, this is the first study to evaluate Rugulopteryx okamurae as a biostimulator . This macroalgae is relevant since it is an invasive species on the Atlantic and Mediterranean coast causing incalculable economic and environmental burdens. Four extracts (UL1, UL2, RU1 and RU2 developed from Ulva and Rugulopteryx, respectively) were foliar applied to Tempranillo plants cultivated under greenhouse conditions. UL1 and RU2 stood out for their capacity to induce defense genes, such as a PR10, PAL, STS48 and GST1, mainly 24 hours after the first application. The increased expression level of these genes agreed with i) an increase in trans-piceid and trans-resveratrol content, mainly in the RU2 treated leaves, and, ii) an increase in jasmonic acid and decrease in salicylic acid. Moreover, an induction of the activity of the antioxidant enzymes was observed at the end of the experiment, with an increase in superoxide dismutase and catalase in the RU2-treated leaves in particular. Interestingly, while foliar fungal diversity was not influenced by the treatments, alga extract amendment modified fungal composition, RU2 application enriching the content of various groups known for their biocontrol activity. Overall, the results evidenced the capacity of Rugulopteryx okamurae for grapevine biostimulation, inducing the activation of several secondary metabolite pathways and promoting the abundance of beneficial microbiota involved in grapevine protection. While further studies are needed to unravel the bioactive compound(s) involved, including conducting field experiments etc., the current findings are the first steps towards the inclusion of Rugulopteryx okamurae in a circular scheme that would reduce its accumulation on the coast and benefit the viticulture sector at the same time.

The outlook for climate change foresees major impacts on vineyards worldwide, shifting pathogens distribution and dynamics demanding more intense plant protection measures in certain regions, increasing viticulture's dependence on phytochemicals and pesticides. However, the European Commission is applying restrictions on their use, encouraging the development of more sustainable strategies efficient for disease control. Seaweeds represent an ecological alternative for a more sustainable production. Previous studies have shown that algae extracts contain compounds capable of reducing the abundance of plant fungal pathogens. Despite it, little is known about the molecular mechanism underlying this response. SEAWINES project is evaluating the efficacy of the foliar application of Ulva ohnoi and Rugulopteryx okamurae extracts to control powdery and downy mildew, in addition to testing their effect on grape and wine quality. To our knowledge, this is the first study evaluating R. okamurae biostimulant capacity and fungicidal effect in viticulture. This macroalgae is relevant since it is an invasive species in our coasts, causing incalculable economic and environmental burdens. We aim to 1- Reduce the usage of chemicals in grapevines; 2- Reduce fungal diseases in viticulture; 3- Valorize polysaccharides from seaweeds; 4- Increase the added-value to wines (ecological and quality); and 5- Provide an alternative use to seaweed biomass, contributing to bio-circular economy and reducing its accumulation in our coasts.

Debido a su diversidad y extensión territorial, Andalucía es una región española que alberga numerosas variedades minoritarias, ofreciendo a la vitivinicultura local la posibilidad de diversificar su producción vitivinícola. Desde 2020, se ha realizado la identificación molecular de 98 ejemplares procedentes de seis zonas con tradición vitivinícola: la Alpujarra (9 individuos) y el Altiplano (2) en Granada; Moguer (12) en Huelva; el Valle de los Pedroches (36) y Montilla-Moriles (32) en Córdoba; el Pago Burujena (7)en Cádiz. Se han empleado trece marcadores microsatélites, entre ellos los nueve recomendados por la OIV. Se han obtenido 31 genotipos distintos, 20 se corresponden a perfiles de variedades ya descritas, los otros 11 no se han identificado previamente. Los perfiles se han integrado en el database del banco de germoplasma de vid “Rancho de la Merced”. Mediante análisis de diversidad genética, se ha determinado en cuales grupos eco-geográficos se colocan los nuevos genotipos identificados. Al tratarse de nuevas variedades con un interés potencial en ser autorizadas, se quiere disponer de clones certificables; por ello, se ha analizado la presencia de los virus del enrollado, del entrenudo corto infeccioso y del jaspeado de la vid, mediante test ELISA.

The IFAPA research center “Rancho de la Merced” (Jerez, Spain) hosts one of the oldest and most diverse grapevine germplasm repositories in Europe, and is aimed at providing feasible solutions to deal with any agronomic trait by exploring its genetic variability and by means of association and Deoxyribonucleic Acid (DNA) editing studies. In this work, we focused on a wine and dual-use grapevine subcollection that consists of 930 accessions. Genetic analysis allowed to identify 521 unique genotypes. After comparing them with several databases, matches were found for 476 genetic profiles while the remaining 45 have not been previously described. Combination with clustering analysis suggested a total pool of 481 Vitis vinifera accessions that included some table cultivars. Several synonymies, homonymies and mislabeling have also been detected. Structure analysis allowed identifying six clusters according to eco-geographic cultivation areas and one additional group including non-vinifera accessions. Diversity analysis pointed out that Spanish Mediterranean varieties are genetically closer to oriental genotypes than to European varieties typical of oceanic and continental climates. The origin of Spanish varieties is discussed in depth considering our data and previous studies. Analysis of molecular variance partition confirmed a well-structured germplasm, although differentiation among groups had a much lower effect on genetic variability than differences within groups, which are strongly related to a very high heterozygosity. A core collection that covers all allele richness is proposed. It is constituted of about 13% of total accessions, and each cluster inferred by structure analysis is represented.

Rosellinia necatrbc is responsible for the white rot root disease of avocado in Southern Spain. Entoleuca sp. is a fungus isolated from roots of these same trees, but it is not pathogenic in avocado. Here, we describe two new species of partitiviruses detected in isolates of the avocado syrnpatric fungi Entoleuca sp. and R. necatrix, termed Entoleuca partitivirus 1 (EnPV1), genus Alphapartitivirus, and Entoleuca partitivirus 2 (EnPV2), genus Betapartitivirus. For both R. necatrix and Entoleuca sp., the dsRNA of the RdRp genomic segment of EnPV1 accumulates at a higher rate than the CP dsRNA, except for a set of Entoleuca sp. isolates where titers of the CP dsRNA are 35-50 times higher than those of the RdRp dsRNA and between 250-380 times higher than the CP dsRNA titers found in the rest of Entoleuca sp. and R. necatrix isolates. For EnPV2, the accumulation rates of the RdRp dsRNA in Entoleuca sp., is in most of the cases, higher than the CP dsRNA. In contrast, in R. necatrix isolates, EnPV2 dsRNA2 generally accumulates at a higher rate. Genetic analysis of the partitiviruses revealed that there is no apparent variation in the nucleotide sequences among the strains. RNA silencing of the partitiviruses appears to be limited in Entoleuca sp., as shown by small RNA sequencing. Finally, the investigation of the presence of these partitiviruses in a fungal collection revealed that they have no role in the pathogenicity of R. necatrix in avocado or in the avirulence of Entoleuca sp. in this host.

Four isolates of Entoleuca sp., family Xylariaceae, Ascomycota, recovered from avocado rhizosphere in Spain were analyzed for mycoviruses presence. For that, the dsRNAs from the mycelia were extracted and subjected to metagenomics analysis that revealed the presence of eleven viruses putatively belonging to families Partitiviridae, Hypoviridae, Megabirnaviridae, and orders Tymovirales and Bunyavirales, in addition to one ourmia-like virus plus other two unclassified virus species. Moreover, a sequence with 98% nucleotide identity to plant endornavirus Phaseolus vulgaris alphaendornavirus 1 has been identified in the Entoleuca sp. isolates. Concerning the virome composition, the four isolates only differed in the presence of the bunyavirus and the ourmia-like virus, while all other viruses showed common patterns. Specific primers allowed the detection by RT-PCR of these viruses in a collection of Entoleuca sp. and Rosellinia necatrix isolates obtained from roots of avocado trees. Results indicate that intra- and interspecies horizontal virus transmission occur frequently in this pathosystem.

The white rot root disease caused by Rosellinia necatrix is a major concern for avocado cultivation in Spain. Healthy escapes of avocado trees surrounded by diseased trees prompted us to hypothesize the presence of hypovirulent R. necatrix due to mycovirus infections. Recently, we reported the presence of another fungal species, Entoleuca sp., belonging to the Xylariaceae, that was also found in healthy avocado trees and frequently co-infecting the same roots than R. necatrix. We investigated the presence of mycoviruses that might explain the hypovirulence. For that, we performed deep sequencing of dsRNAs from two isolates of Entoleuca sp. that revealed the simultaneous infection of several mycoviruses, not described previously. In this work, we report a new member of the Hypoviridae, tentatively named Entoleuca hypovirus 1 (EnHV1). The complete genome sequence was obtained for two EnHV1 strains, which lengths resulted to be 14,958 and 14,984 nt, respectively, excluding the poly(A) tails. The genome shows two ORFs separated by a 32-nt inter-ORF, and both 5'- and 3'-UTRs longer than any other hypovirus reported to date. The analysis of virus-derived siRNA populations obtained from Entoleuca sp. demonstrated antiviral silencing activity in this fungus. We screened a collection of Entoleuca sp. and R. necatrix isolates and found that EnHV1 was present in both fungal species. A genetic population analysis of EnHV1 strains revealed the presence of two main clades, each of them including members from both Entoleuca sp. and R. necatrix, which suggests intra- and interspecific virus transmission in the field. Several attempts failed to cure Entoleuca sp. from EnHV1. However, all Entoleuca sp. isolates collected from avocado, whether harboring the virus or not, showed hypovirulence. Conversely, all R. necatrix isolates were pathogenic to that crop, regardless of being infected by EnHV1.

Background The advances in high-throughput sequencing technologies are allowing more and more de novo assembling of transcriptomes from many new organisms. Some degree of automation and evaluation is required to warrant reproducibility, repetitivity and the selection of the best possible transcriptome. Workflows and pipelines are becoming an absolute requirement for such a purpose, but the issue of assembling evaluation for de novo transcriptomes in organisms lacking a sequenced genome remains unsolved. An automated, reproducible and flexible framework called TransFlow to accomplish this task is described. Results TransFlow with its five independent modules was designed to build different workflows depending on the nature of the original reads. This architecture enables different combinations of Illumina and Roche/454 sequencing data, and can be extended to other sequencing platforms. Its capabilities are illustrated with the selection of reliable plant reference transcriptomes and the assembling six transcriptomes (three case studies for grapevine leaves, olive tree pollen, and chestnut stem, and other three for haustorium, epiphytic structures and their combination for the phytopathogenic fungus Podosphaera xanthii ). Arabidopsis and poplar transcriptomes revealed to be the best references. A common result regarding de novo assemblies is that Illumina paired-end reads of 100 nt in length assembled with OASES can provide reliable transcriptomes, while the contribution of longer reads is noticeable only when they complement a set of short, single-reads. Conclusions TransFlow can handle up to 181 different assembling strategies. Evaluation based on principal component analyses allows its self-adaptation to different sets of reads to provide a suitable transcriptome for each combination of reads and assemblers. As a result, each case study has its own behaviour, prioritises evaluation parameters, and gives an objective and automated way for detecting the best transcriptome within a pool of them. Sequencing data type and quantity (preferably several hundred millions of 2×100 nt or longer), assemblers (OASES for Illumina, MIRA4 and EULER-SR reconciled with CAP3 for Roche/454) and strategy (preferably scaffolding with OASES, and probably merging with Roche/454 when available) arise as the most impacting factors.

HomePlant DiseaseVol. 101, No. 1First Report of Grapevine Red Globe virus in grapevine in Spain PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Grapevine Red Globe virus in grapevine in SpainE. Cretazzo, C. V. Padilla, and L. VelascoE. CretazzoSearch for more papers by this author, C. V. PadillaSearch for more papers by this author, and L. VelascoSearch for more papers by this authorAffiliationsAuthors and Affiliations E. Cretazzo , Instituto Andaluz de Investigación y Formación Agraria (IFAPA), 29140 Churriana, Málaga, Spain C. V. Padilla , Instituto Murciano de Investigación y Desarrollo Agrario (IMIDA), 30150 La Alberca, Murcia, Spain L. Velasco , Instituto Andaluz de Investigación y Formación Agraria (IFAPA), 29140 Churriana, Málaga, Spain. Published Online:11 Oct 2016https://doi.org/10.1094/PDIS-06-16-0932-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat The Spanish Official Grapevine Certification scheme relies on biological indexing for the sanitary evaluation of the candidate clones to certification. Prior to biological assay, propagation material of these clones is screened by ELISA and PCR/qPCR following standard protocols. Occasionally, vines exhibit virus symptoms on indicators; after that, conventional laboratory diagnostics have failed to determine the causal agent for the disease. Next generation sequencing is a robust tool for the determination of all the pathogens present in a given plant. In this context, the indexing of a plant of the Spanish traditional cultivar Godello, originally collected in 2003 in Navarra (Spain), induced mild leafroll-like symptoms in Vitis vinifera cv. Cabernet Sauvignon. No symptoms were induced in V. rupestris du Lot, another indicator host. ELISA and RT-qPCR could not definitively attribute the symptoms to a specific virus species. In order to better establish the etiology of the disease, small RNAs were obtained from bark scrapings of Godello clone 6 using the miRCURY RNA isolation kit (Exiqon, Denmark) and used for Illumina sequencing. The 24.5 million short reads (20 to 49 nt length) obtained were assembled with Velvet 12.08 (kmer = 18) into 3,495 contigs and subjected to BLASTX and BLASTN. BLAST search of the contigs resulted positive for Grapevine leafroll-associated virus 2 (GLRaV-2), Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine Red Globe virus (GRGV), Grapevine virus B (GVB), Hop stunt viroid (HSVd), and Grapevine yellow speckle viroid 1 (GYSVd-1). The leafroll symptoms found in Godello clone 6 could be attributable to a variant of GLRaV-2. From total contigs, 33 of them significantly matched to GRGV sequences available in GenBank and averaging 91.4% pairwise identity to those sequences. The contigs extended the original sequence of the GRGV reference isolate from Italy (2,006 bp length, AF521977) (Abou Ghanem-Sabanadzovic et al. 2003; Martelli et al. 2002) in 275 nt in the 5′ end and none in the 3′ end. The specific primers RG1401F (5′-CGAGACCGGCTTCACCTCCCTGG-3′) and RG1980R (5′-GACTGGGAAACTGCACACTACTA-3′) were designed based on a draft sequence derived from the contigs of CP gene and partial 3′ noncoding region of the GRGV Godello 6 isolate. After RT-PCR, an amplicon of the expected size (576 bp) was obtained and used for cloning and sequencing (KX449333). Comparison of the coat protein encoding region between GRGV Godello 6 isolate and the GRGV reference isolate showed a nucleotide sequence identity of 86.7%. The deduced partial amino acid sequence was 90.1% identical. On the other hand, 15 contigs significantly matched to the sequence we obtained from the cloned RT-PCR amplicon displaying a pairwise identity of 94.0%. GRGV might be well distributed in Spain. In addition to cv. Godello, we have detected the virus in other traditional grapevine cultivars collected in the northern and southern parts of the country. To our knowledge, this is the first report of GRGV in Spain.References:Abou Ghanem-Sabanadzovic, N., et al. 2003. Virus Genes 27:11. https://doi.org/10.1023/A:1025164200412 Crossref, ISI, Google ScholarMartelli, G. P., et al. 2002. Arch. Virol. 147:1847. https://doi.org/10.1007/s007050200046 Crossref, ISI, Google ScholarDetailsFiguresLiterature CitedRelated Vol. 101, No. 1 January 2017SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 22 Dec 2016Published: 11 Oct 2016First Look: 23 Aug 2016Accepted: 18 Aug 2016 Page: 264 Information© 2017 The American Phytopathological SocietyCited byComplete Genome Sequences of Grapevine Red Globe Virus in JapanMicrobiology Resource Announcements, Vol. 11, No. 12First Report of Grapevine Red Globe Virus in Grapevines in Washington StateSridhar Jarugula, Nomatter Chingandu, Jati Adiputra, Basavaraj Bagewadi, Raphael Adegbola, Chandrasekhar Thammina, and Rayapati Naidu6 January 2021 | Plant Disease, Vol. 105, No. 3Vitis vinifera (Grape)6 June 2020First Report of Grapevine Red Globe Virus in Grapevine in GermanyA. B. Ruiz-García, S. Nourinejhad Zarghani, A. Okic, A. Olmos, and T. Wetzel19 June 2018 | Plant Disease, Vol. 102, No. 8NGS of Virus-Derived Small RNAs as a Diagnostic Method Used to Determine Viromes of Hungarian Vineyards6 February 2018 | Frontiers in Microbiology, Vol. 9High-throughput sequencing allowed the completion of the genome of grapevine Red Globe virus and revealed recurring co-infection with other tymoviruses in grapevine25 January 2017 | Plant Pathology, Vol. 66, No. 7Grapevine fleck and similar viruses6 July 2017

Grapevine Red Globe virus (GRGV) is a member of family Tymoviridae tentatively assigned to genus Maculavirus. There is evidence that the distribution of this virus may be widespread. In a recent report, the authors of the present study described the presence of GRGV in Spain. To further estimate its incidence, a survey was carried out that allowed the detection of the virus using RT‐PCR in a germplasm collection in northern Spain. In the present study, three isolates were selected to obtain full‐length genome sequences using high‐throughput sequencing (HTS) of RNA combined with Sanger sequencing. The GRGV complete genome consists of 6850 nucleotides, excluding the polyA tail. Two ORFs could be identified as the putative replicase and coat protein. Although comparison of the complete genomes provided no evidence for the presence of the additional ORF previously described, another ORF was identified within the coat protein ORF, but it probably lacks functional significance. Phylogenetic analysis supported the ascription of GRGV to genus Maculavirus. The profile of vsiRNA (virus‐derived small interfering RNA) distribution along the GRGV genomes suggested the presence of a subgenomic RNA corresponding to the coat protein ORF. To improve detection of GRGV, new primer sets were designed based on consensus sequences. HTS revealed a frequent co‐infection of GRGV and grapevine rupestris vein feathering virus (GRVFV). Biological indexing by grafting two GRGV‐infected vines on indicator plants and the visual inspection of symptoms in other infected plants revealed that the virus has a negligible impact on grapevine.

The complete genome sequence of one isolate of Grapevine leafroll-associated virus 4 strain 9 (GLRaV-4 strain 9) was determined using a library constructed from the sequencing of the small RNA population. The RNA genome consists of 13,858 nucleotides and contains seven open reading frames. A 5' non coding end (218 nt) is followed by ORF1 encoding the 261.5 kDa methyltransferase/helicase domains then, through a + 1 ribosomal frameshift, by ORF1b encoding a 58.28 kDa product corresponding to the replicase RdRp. The ORFs that follow encode the 5.32 kDa P5 protein, the 58.12 kDa HSP70h protein, the 60.18 kDa protein, the 29.9 kDa coat protein and finally the 23.2 kDa p23 protein followed by a 127 nt non coding 3' end. The analysis of virus-derived siRNA populations aligning to the GLRaV-4 strain 9 genome showed a major representation of 21-nt reads, suggesting the involvement of DCL4 in virus silencing. The profile of the vsiRNAs density along the viral genome differed clearly from that of GLRaV-3, the representative member of subgroup I of the genus Ampelovirus, that was present in the same plant.

Aims: The use of healthy propagating material is required to control grapevine viruses. The aim of this work was to eliminate Grapevine fleck virus (GFkV) from a Manto Negro clone, a local grapevine variety, in order to include this material in certification programs. Additionally, the effects of virus elimination on photosynthesis and related parameters were evaluated. Methods and results: Two method combinations for virus elimination were evaluated: (1) field thermotherapy and shoot tip culture and (2) chamber thermotherapy and shoot tip culture. GFkV elimination was tested by double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). The results suggest that a natural field thermotherapy prior to shoot tip culture is effective, making unnecessary the chamber thermotherapy treatment. Additionally, the effects of virus elimination on gas exchanges, chlorophyll fluorescence, electron transport rate (ETR), protein and pigment content were evaluated. The results indicate that GFkV infection affects physiological processes, especially stomatal conductance (gs), whereas photosynthesis, protein, pigment content, ETR, and fluorescence parameters were not significantly changed. Conclusion: This study described a simple and rapid method that requires only one medium for virus elimination (GFkV). Beyond its sanitation potential, the use of larger explants (1-3 mm) ensures the integrity of the clone. The presence of the virus affects physiological processes, especially gs, demonstrating the beneficial effect of eliminating GFkV. Significance and impact of the study: The described method has the potential to produce GFkV-free rooted plantlets faster than other methods while being potentially safer in maintaining the genetic and phenotypic stability of the regenerated clone. The beneficial effects of GFkV elimination provide evidence for the importance to detect this virus prior to the inclusion of clones in certification programs.

Grapevine leafroll ampeloviruses have been recently grouped into two major clades, one for Grapevine leafroll associated virus (GLRaV) 1 and 3 and another one grouping GLRaV-4 and its variants. In order to understand biological factors mediating differential ampelovirus incidences in vineyards, quantitative real-time polymerase chain reactions were performed to assess virus populations in three grapevine varieties in which different infection status were detected: GLRaV-3 + GLRaV-4, GLRaV-3 + GLRaV-4 strain 5, and GLRaV-4 alone. Specific primers based on the RNA-dependent RNA polymerase (RdRp) domains of GLRaV-3, GLRaV-4, and GLRaV-4 strain 5 were used. Absolute and relative quantitations of the three viruses were achieved by normalization of data to the concentration of the endogenous gene actin. In spring, the populations of GLRaV-4 and GLRaV-4 strain 5 were 1.7 × 104 to 5.0 × 105 genomic RNA copies/mg of petiole tissue whereas, for GLRaV-3, values were significantly higher, ranging from 5.6 × 105 and 1.0 × 107 copies mg–1. In autumn, GLRaV-4 and GLRaV-4 strain 5 populations increased significantly, displaying values for genome copies between 4.1 × 105 and 6.3 × 106 copies mg–1, whereas GLRaV-3 populations displayed a less pronounced boost but were still significantly higher, ranging from 4.1 × 106 to 1.6 × 107 copies mg–1. To investigate whether additional viruses may interfere in the quantifications the small RNA populations, vines were analyzed by Ion Torrent high-throughput sequencing. It allowed the identification of additional viruses and viroids, including Grapevine virus A, Hop stunt viroid, Grapevine yellow speckle viroid 1, and Australian grapevine viroid. The significance of these findings is discussed.

In Europe, many autochthonous grapevines (Vitis vinifera L.) are only cultivated at local scale, but play a very important economic role due to their strict relation with terroir and wine tipicity. In this study, it was pursued to evaluate the influence of several factors on performance of Moll, the main autochthonous white variety of Majorca, by means of the database coming from a clonal preselection. The effects of multiple virus infections, vintage and vineyard components were studied by univariate linear models and principal component analysis, starting from measurement of production and must quality parameters of several vines located in 14 vineyards belonging to two appellations during four consecutive years (2001-2004). Absence of multiple virus infections, double cordon system, high clay content and Useful Water Reserve in soils have enhanced vine production without inducing considerable alterations in sugar accumulation in berries and acidity. Moll variety presented great viticultural and oenological potentials. Fertile and deep soils should be preferred in order to maximize production. Also, the use of certified propagation material is strongly recommended. However, further investigations are required to optimize must quality by opportune managements. This study does not provide only essential information to improve Moll cultivation in Majorca, but it also represents a useful example to analyze grapevine varieties that are endemically infected by viruses. In fact, in such situations, it may be supposed an insidious interference by viruses on terroir and wine tipicity.