Garlic viral complex: identification of Potyviruses and Carlavirus in Central Brazil

Abstract

Garlic viruses often occur in complex infections in nature. In this study, a garlic virus complex, collected in fields in Brazil, was purified. RT-PCR was performed using specific primers designed from the consensus regions of the coat protein genes of Onion yellow dwarf virus, a garlic strain (OYDV-G) and Leek yellow stripe virus (LYSV). cDNA of Garlic common latent virus (GCLV) was synthesized using oligo-dT and random primers. By these procedures individual garlic virus genomes were isolated and sequenced. The nucleotide sequence analysis associated with serological data reveals the presence of two Potyvirus OYDV-G and LYSV, and GCLV, a Carlavirus, simultaneously infecting garlic plants. Deduced amino acid sequences of the Brazilian isolates were compared with related viruses reported in different geographical regions of the world. The analysis showed closed relations considering the Brazilian isolates of OYDV-G and GCLV, and large divergence considering LYSV isolate. The detection of these virus species was confirmed by specific reactions observed when coat protein genes of the Brazilian isolates were used as probes in dot-blot and Southern blot hybridization assays. In field natural viral re-infection of virus-free garlic was evaluated.

Detection of three Allexivirus species infecting garlic in Brazil

“…Although serology can be used for Allexivirus detection, it is not suitable for Allexivirus taxonomy. This observation supports the application and need of molecular techniques for characterization of viruses in the garlic virus complex, as demonstrated by other reports (Nagakubo et al, 1994;Tsuneyoshi et al, 1998;Fajardo et al, 2001).…”

“…A Brazilian LYSV isolate infecting garlic plants showed a significantly lower amino acid homology (average of 88.6%) with isolates from distinct geographical areas (Fajardo et al, 2001). For tospoviruses, a Brazilian isolate of Iris yellow spot virus (IYSV), found in naturally infected onion fields, showed 10% diversity in the nucleocapsid protein gene with the IYSV type species described in The Netherlands.…”

“…However, the identity of these pathogens and their relationship with other garlic viruses is still not completely elucidated. Recently in Brazil, potyviruses and carlaviruses naturally infecting garlic plants have been characterized (Fajardo et al, 2001). However, no allexiviruses have been detected.…”

Incidence of Garlic common latent virus in Argentina, and phylogenetic and recombination analyses of isolates

“…GarCLV was mentioned as one of the most frequent viruses affecting garlic crop (Van Dijk, 1993;Tsuneyoshi et al, 1998), being reported in several countries of Asia (Barg et al, 1994;Tsuneyoshi et al, 1998;Pramesh & Baranwal, 2013), Europe (Bellardi et al, 1995;Tsuneyoshi et al, 1998;Dovas et al, 2001;Dovas & Vovlas, 2003;Klukácková et al, 2007;Shahraeen et al, 2008), Oceania, North America (Pappu et al, 2005;Pérez-Moreno et al, 2007), and South America (Conci, 1997;Fajardo et al, 2001;Nieto et al, 2005). A study of GarCLV incidence conducted in Greece showed that infection rates were variable, with up to 97.6% of infected plants in the province of Arcadia (Dovas et al, 2001).…”

Survey of viruses belonging to different genera and species in noble garlic in Brazil

“…They are represented by the Onion yellow dwarf virus (OYDV) and Leek yellow stripe virus (LYSV) species (Chen et al, 2001;Maeso et al, 1997). As regards the Carlavirus genus, the most common species found is the Garlic common latent virus (Gar-CLV) (Fajardo et al, 2001), and Shallot latent virus (SLV) was recently reported in Brazil (Mituti et al, 2011).…”