TAXONOMIC REVISION OF THE FAMILY CLOSTEROVIRIDAE WITH SPECIAL REFERENCE TO THE GRAPEVINE LEAFROLL-ASSOCIATED MEMBERS OF THE GENUS AMPELOVIRUS AND THE PUTATIVE SPECIES UNASSIGNED TO THE FAMILY

New insights into the genetic structure and variability of grapevine leafroll-associated viruses (GLRaVs) gained through worldwide efforts in the last decade or so, and the production and use of new sets of serological reagents, have provided the solid foundation on which the present revision of the taxonomic structure of the family Closteroviridae, and the genus Ampelovirus in particular, is based. A comparative examination of the amino acid sequence divergence of three taxonomically relevant genes [RNA-dependent RNA polymerase (polymerase), heat shock protein 70 homologue (HSP70h) and coat protein (CP)] disclosed a difference among Grapevine leafroll-associated virus 4 (GLRaV-4), -5, -6 and -9 and a group of more recently described viruses (GLRaV-Pr, GLRaV-De and GLRaV-Car) below the 25% limit recently set by the International Committee on Taxonomy of Viruses (ICTV) as a discriminating criterion for the identification of species in the family Closteroviridae. This, plus the recognition that GLRaV-4, -5, -6 and -9 are serologically related, have similar biological and epidemiological traits, and that these viruses and GLRaV-Pr, GLRaV-De, GLRaV-Car have a genome with the same structure and size, supports the notion that they are all genetically divergent variants of a single species, GLRaV-4. The genus Ampelovirus is split into two subgroups designated I and II in recognition of the wide difference in the size and structure of the genome of the present members. Finally, the establishment of a fourth genus within the family Closteroviridae, comprising the unassigned putative species Grapevine leafroll-associated virus 7 (GLRaV-7), Little cherry virus 1 (LChV-1) and Cordyline virus 1 (CoV-1), is justified based on their molecular and biological characteristics that differ from those of members of the other three genera of the family.

[1]  V. Dolja,et al.  Comparative and functional genomics of closteroviruses , 2006, Virus Research.

[2]  R. Bestwick,et al.  Serological Detection of Grapevine Associated Closteroviruses in Infected Grapevine Cultivars. , 1997, Plant disease.

[3]  E. Koonin,et al.  Genomic and biological analysis of Grapevine leafroll-associated virus 7 reveals a possible new genus within the family Closteroviridae. , 2012, Virus research.

[4]  Rodrigo P. P. Almeida,et al.  Grapevine leafroll-associated virus 3 , 2013, Front. Microbiol..

[5]  G. Martelli,et al.  Two grapevine viruses in an ornamental Vitis species from Scotland. , 2005 .

[6]  M. A. Rezaian,et al.  Nucleotide sequence and organization of ten open reading frames in the genome of grapevine leafroll-associated virus 1 and identification of three subgenomic RNAs. , 2000, The Journal of general virology.

[7]  J. Monis,et al.  Partial Genome Organization, Identification of the Coat Protein Gene, and Detection of Grapevine leafroll-associated virus-5. , 2001, Phytopathology.

[8]  N. Katis,et al.  Complete genome analysis and immunodetection of a member of a novel virus species belonging to the genus Ampelovirus , 2008, Archives of Virology.

[9]  P. Gugerli,et al.  Genome organization, serology and phylogeny of Grapevine leafroll-associated viruses 4 and 6: taxonomic implications. , 2012, Virus research.

[10]  C. Jacquet,et al.  Establishment of a relationship between grapevine leafroll closteroviruses 1 and 3 by use of monoclonal antibodies , 2000 .

[11]  D. Golino,et al.  Vitis californica and Vitis californica × Vitis vinifera Hybrids are Hosts for Grapevine leafroll-associated virus-2 and -3 and Grapevine virus A and B. , 2011, Plant disease.

[12]  D. Gonsalves,et al.  Cytopathology of leafroll-diseased grapevines and the purification and serology of associated closteroviruslike particles. , 1987 .

[13]  John S. Hu,et al.  Characterization of closterovirus-like particles associated with grapevine leafroll disease , 1990 .

[14]  V. Dolja,et al.  Retention of the virus-derived sequences in the nuclear genome of grapevine as a potential pathway to virus resistance , 2009, Biology Direct.

[15]  W. Jelkmann,et al.  Replication of Grapevine leafroll-associated virus-7 (GLRaV-7) by Cuscuta Species and Its Transmission to Herbaceous Plants. , 2010, Plant disease.

[16]  D. Boscia,et al.  Grapevine leafroll-associated closterovirus 7 in Greece , 2001 .

[17]  J. Monis.  Development of Monoclonal Antibodies Reactive to a New Grapevine Leafroll-Associated Closterovirus. , 2000, Plant disease.

[18]  F. Faoro,et al.  Localization of Closteroviruses on Grapevine Thin Sections and Their Identification by Immunogold Labelling , 1991 .

[19]  W. Jelkmann,et al.  Transmission of Little cherry virus-1 (LChV-1) by Cuscuta europea to herbaceous host plants. , 2010 .

[20]  M. A. Rezaian,et al.  Hypervariable genes in Grapevine leafroll associated virus 1. , 2001, Virus research.

[21]  B. Walter,et al.  Characterization and Serological Detection of Four Closterovirus‐like Particles Associated with Leafroll Disease on Grapevine , 1990 .

[22]  M. Glasa,et al.  Partial Molecular Characterization of a Czech Isolate of Grapevine leafroll-associated virus 3 , 2004 .

[23]  H F Kern,et al.  Selection of AUG initiation codons differs in plants and animals. , 1987, The EMBO journal.

[24]  J. Monis,et al.  First Detection of Grapevine leafroll associated virus-7 in California Vineyards. , 2007, Plant disease.

[25]  D. Golino,et al.  PARTIAL CHARACTERIZATION OF A NEW AMPELOVIRUS ASSOCIATED WITH GRAPEVINE LEAFROLL DISEASE , 2004 .

[26]  Alan Little.  Complete sequence, improved detection and functional analysis of Grapevine Leafroll-associated Virus 1(GLRaV-1) / by Alan Little. , 2004 .

[27]  N. Katis,et al.  Evolutionary relationships of virus species belonging to a distinct lineage within the Ampelovirus genus. , 2008, Virus research.

[28]  D. Golino,et al.  A putative new ampelovirus associated with grapevine leafroll disease , 2010, Archives of Virology.

[29]  Molecular characterization and taxonomy of grapevine leafroll-associated virus 7 , 2012, Archives of Virology.

[30]  D. Golino,et al.  Mealybug transmission of Grapevine leafroll viruses: an analysis of virus-vector specificity. , 2010, Phytopathology.

[31]  S. Namba,et al.  Grapevine Leafroll Virus, a Possible Member of Closteroviruses , 1979 .

[32]  John S. Hu,et al.  An assemblage of closteroviruses infects Hawaiian ti (Cordyline fruticosa L.) , 2011, Virus Genes.

[33]  R. Naidu,et al.  Grapevine leafroll-associated virus 1 occurs as genetically diverse populations. , 2011, Phytopathology.

[34]  L. R. Krake,et al.  Characterization of grapevine leafroll disease by symptomatology. , 1993 .

[35]  M. Fuchs,et al.  Genomic analysis of grapevine leafroll associated virus-5 and related viruses. , 2012, Virus research.

[36]  V. Dolja,et al.  The family Closteroviridae revised , 2002, Archives of Virology.

[37]  A. Karasev.  Genetic Diversity and Evolution of Closteroviruses. , 2000, Annual review of phytopathology.

[38]  G. Martelli,et al.  PARTIAL CHARACTERISATION OF A GRAPEVINE LEAFROLL- ASSOCIATED VIRUS ISOLATED FROM AN INFECTED CYPRIOT VINE OF cv. MAVRO , 2009 .