Grapevine rupestris stem pitting-associated virus(GRSPaV),a member of the genusFoveavirusin the familyBetaflexiviridae, has a high genetic variability (Meng andRowhani2017 ); some strains are putatively associated withRupestris stem-pitting disease, a component of the RugoseWood complex of the grapevine. To assess the viral status ofgrapevine in Meknès region (the central part of Morocco), a totalof 35 samples of cv.'Cinsaut'were randomly collected in 2013from the same vineyard. After total RNA extraction and cDNAsynthesis, the presence of GRSPaV was checked by PCR usingtwo sets of primers: RSP-52 (5?-TGAAGGCTTTAGGGGTTAG-3?) and RSP-53 (5?-CTTAACCCAGCCTTGAAAT-3?) that amplify the complete (905 bp) coat protein (CP) gene(Rowhani et al.2000)andRSPaV13(5?-GATGAGGTCCAGTTGTTTCC-3?)andRSPaV14(5?-ATCCAAAGGACCTTTTGACC-3?) that amplify a partial fragment(338 bp) within the helicase domain of ORF1 (Meng et al.1999). Five samples reacted positively and showed ampliconsof the expected sizes using both sets of primers. PCR products ofthe CP gene originated from the positive samples were purifiedand sequenced in both directions. The obtained sequences wereidentical; one of those sequences was deposited in GenBank(accession number MH156797). Nucleotide blast analysis ofthe Moroccan isolate showed 98% sequence identity with a French one within group I (SGM5-1; KX035004). To ourknowledge, this is the first report of GRSPaV infecting grape-vine in Morocco. Even if the number of the tested samples wasrelatively low, this result can help to understand the incidence ofGRSPaV that seems to be unexpectedly low if compared toother reports (Meng and Rowhani2017). Due to the self-rooted condition of the old vineyard visited in the Meknes area,this low GRSPaV infection rate (five positive samples out of 35tested) is conceivable, as this virus essentially spreads throughvegetative propagation of infected sources or grafting with in-fected rootstocks. Moreover, (i) the strict homology with aFrench isolate could reflect the most likely common origin ofthis propagation material certainly before the introduction ofgrafting on American rootstocks, (ii) GRSPaV has no knownvector, thus the local spread of mixed infections could have beenhappened only through overgrafting with budwood bearing dif-ferent strains; finally (iii) the identification of a single dominantmolecular variants is likely due to the direct sequencingof PCR products, that may conceal minor variants pres-ent in lower concentration. Further and wider investigationswill disclose the clear picture of the GRSPaV relevance inMoroccan grape germplasm (21) (PDF) First report on the occurence of grapevine rupestris stem pitting-associated virus in Moroccan grapevines. Available from: https://www.researchgate.net/publication/328037210_First_report_on_the_occurence_of_grapevine_rupestris_stem_pitting-associated_virus_in_Moroccan_grapevines [accessed Nov 17 2019].
First report on the occurence of grapevine rupestris stem pitting-associated virus in Moroccan grapevines
Minafra A;Saldarelli P;
2018
Abstract
Grapevine rupestris stem pitting-associated virus(GRSPaV),a member of the genusFoveavirusin the familyBetaflexiviridae, has a high genetic variability (Meng andRowhani2017 ); some strains are putatively associated withRupestris stem-pitting disease, a component of the RugoseWood complex of the grapevine. To assess the viral status ofgrapevine in Meknès region (the central part of Morocco), a totalof 35 samples of cv.'Cinsaut'were randomly collected in 2013from the same vineyard. After total RNA extraction and cDNAsynthesis, the presence of GRSPaV was checked by PCR usingtwo sets of primers: RSP-52 (5?-TGAAGGCTTTAGGGGTTAG-3?) and RSP-53 (5?-CTTAACCCAGCCTTGAAAT-3?) that amplify the complete (905 bp) coat protein (CP) gene(Rowhani et al.2000)andRSPaV13(5?-GATGAGGTCCAGTTGTTTCC-3?)andRSPaV14(5?-ATCCAAAGGACCTTTTGACC-3?) that amplify a partial fragment(338 bp) within the helicase domain of ORF1 (Meng et al.1999). Five samples reacted positively and showed ampliconsof the expected sizes using both sets of primers. PCR products ofthe CP gene originated from the positive samples were purifiedand sequenced in both directions. The obtained sequences wereidentical; one of those sequences was deposited in GenBank(accession number MH156797). Nucleotide blast analysis ofthe Moroccan isolate showed 98% sequence identity with a French one within group I (SGM5-1; KX035004). To ourknowledge, this is the first report of GRSPaV infecting grape-vine in Morocco. Even if the number of the tested samples wasrelatively low, this result can help to understand the incidence ofGRSPaV that seems to be unexpectedly low if compared toother reports (Meng and Rowhani2017). Due to the self-rooted condition of the old vineyard visited in the Meknes area,this low GRSPaV infection rate (five positive samples out of 35tested) is conceivable, as this virus essentially spreads throughvegetative propagation of infected sources or grafting with in-fected rootstocks. Moreover, (i) the strict homology with aFrench isolate could reflect the most likely common origin ofthis propagation material certainly before the introduction ofgrafting on American rootstocks, (ii) GRSPaV has no knownvector, thus the local spread of mixed infections could have beenhappened only through overgrafting with budwood bearing dif-ferent strains; finally (iii) the identification of a single dominantmolecular variants is likely due to the direct sequencingof PCR products, that may conceal minor variants pres-ent in lower concentration. Further and wider investigationswill disclose the clear picture of the GRSPaV relevance inMoroccan grape germplasm (21) (PDF) First report on the occurence of grapevine rupestris stem pitting-associated virus in Moroccan grapevines. Available from: https://www.researchgate.net/publication/328037210_First_report_on_the_occurence_of_grapevine_rupestris_stem_pitting-associated_virus_in_Moroccan_grapevines [accessed Nov 17 2019].I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
