Molecular Plant Pathology – Pathogen Profiles

Turnip mosaic virus and the quest for durable resistance

John A. Walsh and Carol E. Jenner

Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK

Taxonomy:Turnip mosaic virus (TuMV) is a member of the genus Potyvirus (type species Potato virus Y) in the family Potyviridae. To date, TuMV is the only potyvirus known to infect brassicas. There are potyvirus isolates that appear serologically similar to TuMV when tested with polyclonal antisera that do not readily infect brassicas (Lesemann and Vetten, 1985).

Physical properties:Virions are ~720×15-20 nm flexuous rods (Fig. 1) and are composed of 95% coat protein (CP) and 5% RNA.

Host Range:TuMV has been isolated from a wide range of crop and weed plant species. It is known to infect at least 318 species in over 43 dicot families, including CruciferaeCompositaeChenopodiaceaeLeguminosae and Caryophyllaceaeand is also known to infect monocots. It has the broadest known host range in terms of plant genera and families of any potyvirus.

Transmission:Aphid transmitted in the non-persistent manner, by at least 89 species, including Myzus persicae and Brevicoryne brassicae.

Fig. 1 Electron micrograph of TuMV virions
stained with methylamine tungstate. 
Courtesy of Colin Clay, HRI Wellesbourne.

Fig. 2 TuMV infection of wallflower
showing typical flower-breaking symptoms.