Non-enveloped, flexuous and exceptionally long, filamentous particles about 950-2200 nm in length and 10-13 nm in diameter. The virion body is assembled by the major capsid protein (CP) and the tail by the minor capsid protein (CPm).



Mono-(Ampelovirus, Closterovirus) or bi-partite (Crinivirus), linear ssRNA(+) genome of 15 to 20 kb. 3' terminus has no poly(A) tract and the 5' terminus probably has a methylated nucleotide cap.


The virion RNA is infectious and serves as both the genome and viral messenger RNA. ORF1a and ORF1ab protein (containing RdRp) are produced by ribosomal frameshifting. Other ORFs are translated from a set of nested 3' co-terminal subgenomic RNAs.



  1. Virus penetrates into the host cell.
  2. Uncoating, and release of the viral genomic RNA into the cytoplasm.
  3. The viral RNA is translated into a processed ORF1 polyprotein to yield the replication proteins.
  4. Replication occurs in viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
  5. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  6. Subgenomic RNA translation gives rise to the other viral proteins.
  7. Assembly of new virus particles.
  8. Viral movement proteins mediate virion cell-to-cell transfer.

Host-virus interaction

Suppression of RNA silencing

Citrus tristeza virus p25, p20 and p23 and Beet yellows virus p21 and function as suppressors of RNA silencing

Sweet potato chlorotic stunt virus and Tomato chlorosis virus p22 proteins also function as suppressors of RNA silencing

Matching UniProtKB/Swiss-Prot entries

31 entries grouped by strain (browse by keywords)

13 entries

Grapevine leafroll-associated virus 3 (isolate United States/NY1) (GLRaV-3) (Grapevine leafroll-associated closterovirus (isolate 109)) reference strain

P7_GLRV3 Protein P7 (7 kDa protein)
R1AB_GLRV3 Replicase polyprotein 1ab [Cleaved into: Leader protease (L-Pro) (EC 3.4.22.-) (Papain-like cysteine ...
CPM_GLRV3 Minor capsid protein (CPm)
CAPSD_GLRV3 Capsid protein (CP) (Coat protein)
MVP1_GLRV3 Movement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
P6_GLRV3 Uncharacterized 6 kDa protein (p6)
P20B_GLRV3 Protein P20B (19.7 kDa protein)
P55_GLRV3 Protein P55
R1A_GLRV3 Replicase protein 1a [Cleaved into: Leader protease (L-Pro) (EC 3.4.22.-) (Papain-like cysteine ...
P21_GLRV3 Protein P21 (21 kDa protein)
MVP2_GLRV3 Movement protein p5 (5 kDa protein) (Protein P5)
P20A_GLRV3 Protein P20A (19.6 kDa protein)
P4_GLRV3 Protein P4 (4 kDa protein)

9 entries

Lettuce infectious yellows virus (isolate United States/92) (LIYV) reference strain

R1AB_LIYV9 Replicase polyprotein 1ab [Cleaved into: Leader protease (L-PRO) (EC 3.4.22.-); ...
R1A_LIYV9 Replicase polyprotein 1a [Cleaved into: Leader protease (L-PRO) (EC 3.4.22.-); ...
P9_LIYV9 Protein P9
CAPSD_LIYV9 Capsid protein (CP) (Coat protein)
CPM_LIYV9 Minor capsid protein (CPm)
MVP_LIYV9 Movement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
P26_LIYV9 Protein p26
P59_LIYV9 Protein p59
P34_LIYV9 RNA-binding P34 protein (P34)

8 entries

Beet yellows virus (isolate Ukraine) (BYV) (Sugar beet yellows virus) reference strain

CPM_BYVU Minor capsid protein (CPm) (p24)
MVP1_BYVU Movement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
CAPSD_BYVU Capsid protein (CP) (p22)
P20_BYVU 20 kDa protein (p20)
R1AB_BYVU Replicase polyprotein 1ab [Cleaved into: Leader protease (L-Pro) (EC 3.4.22.-) (Papain-like cysteine ...
P21_BYVU RNA silencing suppressor (21 kDa protein) (p21)
MVP2_BYVU Movement protein p6 (6 kDa protein) (p6)
P64_BYVU 64 kDa protein (p64)

1 entry

Citrus tristeza virus (isolate T36) (CTV)

CAPSD_CTV36 Capsid protein (CP) (Coat protein)