Biology:Grapevine leafroll-associated virus 3
| Grapevine leafroll-associated virus 3 | |
|---|---|
Virus classification 
| |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Kitrinoviricota |
| Class: | Alsuviricetes |
| Order: | Martellivirales |
| Family: | Closteroviridae |
| Genus: | Ampelovirus |
| Species: | Ampelovirus trivitis
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Grapevine leafroll-associated virus 3 (GLRaV-3) is a positive-sense single-stranded RNA plant virus in the family Closteroviridae, genus Ampelovirus.[1][2]
It is the principal causal agent of grapevine leafroll disease (GLD), a globally distributed disease complex that reduces yield and fruit quality in Vitis vinifera. Natural transmission is by mealybugs and soft scale insects; the virus is also disseminated via infected propagation material.
Taxonomy and classification
GLRaV-3 belongs to the genus Ampelovirus within the family Closteroviridae.[1] Viruses of Ampelovirus characteristically have long flexuous filamentous particles and are transmitted by mealybugs or soft scale insects. GLRaV-3 shares these features and has been continually refined in classification as more variants were discovered.
Genome and molecular biology
The genome of GLRaV-3 is around 18–19 kb, encoding approximately 12 ORFs including the replication module (papain-like protease, methyltransferase, helicase, RdRP), HSP70h, the major coat protein (CP) and minor coat protein (CPm), plus small accessory ORFs.[1] There is substantial genetic variation among isolates: multiple phylogenetic groups have been defined, and certain variants lack ORF2 or have divergent genomic regions.[2]
Symptoms and disease
In red-fruited grape cultivars, GLD symptoms typically include interveinal reddening of leaves with green veins, leaf rolling downward, and delayed ripening of fruit. In white-fruited cultivars, symptoms may be less dramatic—leaf chlorosis (yellowing) and rolling may occur.[3]
Infected vines can show reduced sugar accumulation (Brix), increased acidity, lower anthocyanin in red grapes, lower vigor, and diminished yield—often tens of percent compared to healthy vines.[4]
Transmission and epidemiology
GLRaV-3 is spread primarily via two routes: (1) through infected propagation material (grafts, cuttings, rootstocks), and (2) via insect vectors—especially mealybugs (family Pseudococcidae) and certain soft scale insects (Coccidae).[4] For example, experiments with the vine mealybug (Planococcus ficus) demonstrated semipersistent transmission: acquisition and inoculation within ~24 h, retention up to several days, and first-instar crawlers being more efficient than adults.[5]
Management
There is no cure for infected vines, so management focuses on prevention and containment. Key strategies include:
1. Planting certified virus-tested (“clean”) propagation material.[3]
2. Mapping and removing (roguing) infected vines early to minimise spread.[4]
3. Controlling vector populations (mealybugs and scales) using integrated pest management: monitoring, insecticide treatments upon crawler emergence, biological controls, and pheromone-based mating disruption.[3]
References
- ↑ 1.0 1.1 1.2 "Grapevine leafroll-associated virus 3". Front Microbiol 4: 82. 2013. doi:10.3389/fmicb.2013.00082. PMID 23596440.
- ↑ 2.0 2.1 "A divergent variant of Grapevine leafroll-associated virus 3 is present in California". Virol. J. 9: 235. 2012. doi:10.1186/1743-422X-9-235. PMID 23062082.
- ↑ 3.0 3.1 3.2 "Ecology and management of grapevine leafroll disease". Frontiers in Microbiology 4: 94. 2013. doi:10.3389/fmicb.2013.00094. PMID 23630520.
- ↑ 4.0 4.1 4.2 "Retention and transmission of Grapevine leafroll-associated virus 3". Frontiers in Microbiology 12. 2021. doi:10.3389/fmicb.2021.663948.
- ↑ "Mealybug transmission of grapevine leafroll viruses: an analysis of virus–vector specificity". Phytopathology 100 (8): 830-834. 2010. doi:10.1094/PHYTO-100-8-0830.
External links
Wikidata ☰ Q18345922 entry
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