Closteroviridae

Abstract

Closteroviridae is a family of plant viruses with filamentous, helically constructed particles showing distinct cross‐banding and varying in length from 650 nm (species with fragmented genome) to over 2000 nm (species with monopartite genome). The genome is a single‐stranded, positive‐sense ribonucleic acid , with size varying from 13 000 to nearly 19 000 nucleotides, thus being among the largest known for plant viruses. The family comprises four genera, Closterovirus , Ampelovirus , Crinivirus and Velarivirus , which differ in genome type (monopartite, bipartite or tripartite) and size, and in epidemiological behaviour. Closteroviruses are transmitted by aphids; ampeloviruses by pseudococcid mealybugs and soft scale insects and criniviruses by whiteflies. No vectors are known for velariviruses. These viruses are mostly phloem‐restricted. Except for velariviruses all are transmitted with a semipersistent modality regardless of the type of vector and are pathogenic to a wide range of herbaceous and woody crops, to which they may cause extensive damage. Control is based on preventive measures such as sanitary selection, sanitation and induction of resistance, primarily through conventional breeding. Key Concepts: Closteroviridae is a growing family of plant viruses with currently four genera. All members of the family have filamentous virions with open particle structures and distinct cross‐banding. Closteroviral genomes are among the largest for plant viruses and are highly diversified also within each genus. The family represents a monophyletic lineage that has evolved in a modular way. A characterising trait of three genera ( Closterovirus, Ampelovirus and Crinivirus ) is the type of vectors that mediate transmission from host to host. Virus particles are primarily restricted to the phloem from where they are acquired by the vectors. Virus dissemination over long distances is mediated by infected propagative material, rather than vectors. Most members of the family have a restricted natural host range. Disease control relies on preventive measures aimed at reducing vector populations and sources of inoculum. Sanitary selection and sanitation are efficient means for producing certified stocks.

Transmission of Grapevine Leafroll-associated Virus 3 (GLRaV-3): Acquisition, Inoculation and Retention by the Mealybugs Planococcus ficus and Pseudococcus longispinus (Hemiptera: Pseudococcidae)

“…ficus nymphs can acquire GLRaV-3 in 15 min and transmit the virus to healthy plants, and that viruliferous nymphs can inoculate healthy plants within 15 min. This is in accordance with other Hemiptera-transmitted Closteroviridae (Martelli & Candresse, 2014). Previous work on the transmission of GLRaV-3 by Ps.…”

High codon adaptation in citrus tristeza virus to its citrus host

“…CTV causes tremendous economic losses to the citrus industries worldwide [22]. CTV is a non-enveloped, single-stranded positive-sense RNA virus belonging to the genus Closterovirus in the family of Closteroviridae [23]. Genome RNA (gRNA) of CTV is approximately 19.3 kb in length and contains 12 open reading frames (ORFs) that from the 5' to the 3' end are ORF1a ORF1b p33 p6 p65 p61 p27 (encodes the minor coat protein), p25 (encodes the major coat protein), p18 p13 p20 , and p23 .…”

Pest categorisation of Citrus tristeza virus (non‐European isolates)

“…Citrus tristeza virus is a well characterised virus in the genus Closterovirus of the Closteroviridae family (Karasev and Bar‐Joseph, ; Martelli et al., ). It has a large, ca.…”