Polymyxa graminis and the cereal viruses it transmits: A research challenge

Abstract

Polymyxa graminis is a eukaryotic obligate biotrophic parasite of plant roots that belongs to a poorly studied discrete taxonomic unit informally called the 'plasmodiophorids'. P. graminis is non-pathogenic, but has the ability to acquire and transmit a range of plant viruses which cause serious diseases in cereal crop species and result in significant yield reductions. The viruses are protected from the environment within P. graminis resting spores ('cysts') that may remain dormant but viable for decades (probably until a suitable host plant is encountered). The persistent, soil-borne nature of these diseases makes the use of virus-resistant crop varieties currently the only practical and environmentally friendly means of control.