FIRST REPORT OF GRAPEVINE LEAFROLLASSOCIATED VIRUS 2 IN MOROCCAN VINEYARDS
M. Afechtal, I. Bibi, A. Aarabe, M. Sbaghi, M. Ouantar, Z. Faddoul
With an area of cultivation of about 44,600 ha, grapevines rank fourth among fruit crops of Morocco and represent one of the most valuable crops for the country’s economy. Grapevine leafroll disease, caused by the grapevine leafroll-associated viruses (family Closteroviridae) is one of the most important viral diseases of grapevines (Vitis vinifera) worldwide (Fuchs et al., 2009). During 2014, a number of vineyards of different sizes were visited in Gharb region in order to assess their sanitary status. Grapevines with typical leaf roll symptoms were reported on cultivar ‘Red Globe’ from one vineyard. The symptoms included red leaves and downwardly rolled leaf margins. A total of six samples were collected from vines showing virus symptoms in addition to ten samples from apparently symptomless plants. These samples were subjected to ELISA test, using commercially available kits (Bioreba, Germany), for the presence of Grapevine leafroll associated virus 1, 2 and 3 (GLRaV-1, -2 and -3). Symptomatic vines tested positive for GLRaV-2 and one symptomless plant tested positive to GLRaV-3, previously detected in Morocco (Digiaro et al., 1999); all other ELISA tests were negative. Total nucleic acid was extracted from the samples using RNaesy Plant Mini Kit (Qiagen, Germany) and tested by RT-PCR employing specific primers to amplify a 334 bp fragment of the HSP70h gene of GLRaV-2 (L2 F: 5′-ATAATTCGGCGTACATCCCCACTT- 3′ and U2 R: 5′-GCCCTCCGCGCAACTAATGACAG-3′) (Bertazzon and Angelini, 2004). The RT-PCR assays were also positive for the six symptomatic vines and the ten asymptomatic plants were negative for GLRaV-2, thus confirming the results obtained by ELISA. To the best of our knowledge, this study represents the first report of the occurrence of GLRaV-2 in Morocco.