Analyses of the complete sequence of the genome of wheat Eqlid mosaic virus, a novel species in the genus Tritimovirus

Abstract

The complete nucleotide sequence of the genome of wheat Eqlid mosaic virus (WEqMV) (excluding the poly A tail) comprised 9636 nucleotides including 5' and 3' noncoding regions of 137 and 172 nt, respectively. It contained a single ORF coding for a polyprotein of 3,109 amino acid residues and had a deduced genome organization typical of members of the family Potyviridae and with proteinase cleavage sites very similar to those of the members of the genus Tritimovirus. Pairwise and multiple alignments and phylogenetic analysis showed that WEqMV is a distinct species in the genus Tritimovirus. WEqMV and Wheat streak mosaic virus (WSMV) shared the greatest nucleotide sequence identity in the NIb and HC-Pro cistrons (63.2% and 60.8%, respectively) and the lowest sequence identity in the P1 and CP cistrons (51.2% and 51.1%, respectively). Sequence identity for the complete genome of WEqMV and WSMV was 56.8% at the nucleotide level and 50.7% at the amino acid level. WEqMV had 57.2% nucleotide identity and 50.6% amino acid identity with Oat necrotic mottle virus and 52.5% nucleotide identity and 45.5% amino acid identity with Brome streak mosaic virus. The relationship of WEqMV with other members of the family Potyviridae was more distant. Structural analysis of WEqMV protein showed presence of potential transmembrane helices in 6k1, 6k2, and P3 proteins.

Phylogenetics and evolution of wheat streak mosaic virus: Its global origin and the source of the Australian epidemic

“…WSMV is a tritimovirus, a genus of six known species with strong Eurasian ties (Rabenstein et al, 2002) and, as mentioned in the Introduction, it occurs worldwide (CABI, 2020; Jones, 2021; Singh et al, 2018). However, four other tritimoviruses have only been found in Eurasia infecting Eurasian plants belonging to the Poaceae; brome streak mosaic virus isolated from Bromus mollis in the Czech Republic (Miličić et al, 1980), tall oatgrass mosaic virus from Arenatherum elatius in the Czech Republic (Hassan et al, 2014), wheat Eqlid mosaic virus named after a town in the Zagros Mountains (Rastegar et al, 2008) and yellow oat‐grass mosaic virus from Trisetum flavescens in the Czech Republic (Hassan, 2014). The sixth tritimovirus, ONMV, was found first in Manitoba, Canada, in a crop of Russell oats (Gill & Westdal, 1966; Stenger & French, 2004), a cultivar developed in Canada from a backcross between the Eurasian lines Gary Mutica Ukraine × Abegweit (Zillinsky, 1961), but soon after ONMV was also reported in the Trakya region of Turkey from a serologically based cereal virus survey (İlbaği et al, 2005).…”

Identification and characterization of a novel Tritimovirus species isolated from wild Trisetum flavescens L., family Poaceae

“…Potyviridae genera are distinguished based on their vector and their RNA-genome sequences; two mite-vectored species in the genera Rymovirus and Tritimovirus, aphid-vectored Potyvirus and funga-vectored Bymovirus. Genus Tritimovirus comprises of Wheat streak mosaic virus (WSMV) designated as the type species, Brome streak mosaic virus (BsMV), Oat necrotic mottle virus (ONMV) and Wheat eqild mosaic virus (WEqMV) [4][5][6][7].…”