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)

All proteins are shown (view only 30 complete proteome entries)

13 entries

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

Select_all Deselect_all  
CAPSD_GLRV3Capsid protein (CP) (Coat protein)
CPM_GLRV3Minor capsid protein (CPm)
MVP1_GLRV3Movement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
MVP2_GLRV3Movement protein p5 (5 kDa protein) (Protein P5)
P20A_GLRV3Protein P20A (19.6 kDa protein)
P20B_GLRV3Protein P20B (19.7 kDa protein)
P21_GLRV3Protein P21 (21 kDa protein)
P4_GLRV3Protein P4 (4 kDa protein)
P55_GLRV3Protein P55
P6_GLRV3Uncharacterized 6 kDa protein (p6)
P7_GLRV3Protein P7 (7 kDa protein)
R1AB_GLRV3Replicase polyprotein 1ab
R1A_GLRV3Replicase protein 1a

9 entries

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

Select_all Deselect_all  
CAPSD_LIYV9Capsid protein (CP) (Coat protein)
CPM_LIYV9Minor capsid protein (CPm)
MVP_LIYV9Movement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
P26_LIYV9Protein p26
P34_LIYV9RNA-binding P34 protein (P34)
P59_LIYV9Protein p59
P9_LIYV9Protein P9
R1AB_LIYV9Replicase polyprotein 1ab
R1A_LIYV9Replicase polyprotein 1a

8 entries

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

Select_all Deselect_all  
CAPSD_BYVUCapsid protein (CP) (p22)
CPM_BYVUMinor capsid protein (CPm) (p24)
MVP1_BYVUMovement protein Hsp70h (Heat shock protein 70 homolog) (Hsp70h)
MVP2_BYVUMovement protein p6 (6 kDa protein) (p6)
P20_BYVU20 kDa protein (p20)
P21_BYVURNA silencing suppressor (21 kDa protein) (p21)
P64_BYVU64 kDa protein (p64)
R1AB_BYVUReplicase polyprotein 1ab

1 entry

Citrus tristeza virus (isolate T36) (CTV)

CAPSD_CTV36Capsid protein (CP) (Coat protein)