All members of the genus Deltapartitivirus infect plants. Deltapartitiviruses have two dsRNA segments that are believed to be individually encapsidated in separate particles and the genome is typically 3.1–3.2 kbp in total.
The virions of pepper cryptic virus 1 and pepper cryptic virus 2 are isometric and approximately 30 nm in diameter (Sabanadzovic and Valverde 2011).
Physicochemical and physical properties
Virions of beet cryptic virus 2 have a buoyant density of 1.36 g cm−3 in CsCl gradients (Accotto and Boccardo 1986).
Viral genome comprises two dsRNA segments, which are individually about 1.6–1.7 and 1.4–1.6 kbp.
There is a single major coat protein (CP) with predicted Mr ranging from 38 to 49 kDa. The Mr of the RNA-dependent RNA polymerase (RdRP), as predicted from nucleotide sequence analysis, is approximately 54 kDa. Virion-associated RNA polymerase activity is present.
Genome organization and replication
Each genome segment is monocistronic: dsRNA1 codes for the RdRP and dsRNA2 codes for the major CP. Additional dsRNA segments representing second versions of dsRNA2 and encoding seemingly full-length capsid proteins with unknown function have been detected in several deltapartitiviruses, including beet cryptic virus 2 (HM560704), Fragaria chiloensis cryptic virus (DQ355439), Raphanus sativus cryptic virus 2 (DQ218038) and Rose cryptic virus 1 (EU413668). Deltapartitiviruses do not usually have long poly(A) tracts near the plus-strand 3′-terminus of their genome segments.
Deltapartitiviruses induce persistent infections in plants. They are transmitted by ovule and by pollen to the seed embryo.
Species demarcation criteria
The species demarcation criteria within genus Deltapartitivirus are:
- ≤ 90% aa sequence identity in the RdRP, and
- ≤ 80% aa sequence identity in the CP
|Species||Virus name||Isolate||Accession number||RefSeq number||Available sequence||Virus Abbrev.|
|Beet cryptic virus 2||beet cryptic virus 2||Hungary||RNA1: HM560702;|
RNA2: NC_ 038846;
|Beet cryptic virus 3||beet cryptic virus 3||Xie||RNA2: S63913||RNA2: NC_043394||Partial genome||BCV3|
|Fig cryptic virus||fig cryptic virus||BN13||RNA1: FR687854;|
|Pepper cryptic virus 1||pepper cryptic virus 1||Jal-01||RNA1: JN117276;|
|Pepper cryptic virus 2||pepper cryptic virus 2||HW-01||RNA1: JN117278;|
|Pepper cryptic virus 2||pepper cryptic virus 2||YY||RNA1: LC195294;|
Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.
Related, unclassified viruses
|Fragaria chiloensis cryptic virus isolate NCGR CFRA 9089|
Raphanus sativus cryptic virus 2
|rose cryptic virus 1 isolate ShB-1|
|persimmon cryptic virus isolate SSPI|