Incidence and genetic diversity of grapevine leafroll-associated virus 3 (GLRaV-3) isolates in Turkey

Abstract

Grapevine leafroll-associated virus 3 (GLRaV-3) is the most important virus species within the grapevine leafroll complex. It causes significant losses to growers and vineries because of its effect on grape and wine quality. A survey was conducted in the major grape-growing provinces of Turkey in 2018 to investigate distribution and the genetic diversity of GLRaV-3 in local and foreign grapevine cultivars. The genetic diversity of GLRaV-3 isolates based on partial heat-shock protein 70 homologue (Hsp70 h), partial coat protein (CP) and partial RNA-dependent RNA polymerase (RdRp) genes were determined by RT-PCR and sequencing. The infection rate of GLRaV-3 in 141 tested grapevine samples was 13.47% by DAS-ELISA and 28.36% by RT-PCR analysis. Totally, 17 amplicons from Hsp70 h, 22 isolates from RdRp and 16 isolates from CP genes were sequenced in both directions. The sequence analysis of three genes revealed that the Turkish GLRaV-3 isolates shared 91–100% nucleotide identities with the sequences of GLRaV-3 isolated deposited in the GenBank from other parts of the world without any correlation between the distribution and geographical origin.