Notes on Genus: Badnavirus

bacilliform
bacilliform

Type member: Commelina yellow mottle virus

Contents

General Description

This is one of 7 genera in the family Caulimoviridae, which are distinctive amongst plant viruses in having double-stranded DNA. Members of the badnavirus genus (bacilliform DNA viruses) are those with bacilliform, rather than isometric particles and with 3 open reading frames in the genome. They are also known as the Commelina yellow mottle virus group. Viruses previously classified in this genus but which have 4 open reading frames are now classified in the genus Tungrovirus.

Morphology

Virions bacilliform, not enveloped, about 30 nm in diameter and varying in length between 60-900 nm, depending upon the species.

Genome

Monopartite, open circular, double stranded DNA of 7000-7600 base pairs with a single-strand discontinuity at one site in each strand.

Genus Genomic Organization

The genome has direct terminal repeats, reiterated internally in inverted form and is translated from 3 open reading frames (ORFs) on the same DNA strand. The largest of the ORFs is probably a polyprotein, subsequently processed into several functional products.

Type Member Genomic Organization

There are 3 open reading frames on the same DNA strand:

ORF1, putative 23 kDa product
ORF2, putative 15 kDa product
ORF3, putative 216 kDa polyprotein, subsequently processed into several functional products.