Eragrostis minor streak virus: an Asian streak virus in Africa

Abstract

The genus Mastrevirus of the single-stranded DNA virus family Geminiviridae consists of four distinct virus lineages that have been sampled in different parts of the Old World. These include the Panicoideae-infecting African streak viruses (ten described species including the geographical outlier, Digitaria streak virus [DSV] from Vanuatu) and Australian striate mosaic viruses (three described species), the dicotyledonous-plant-infecting mastreviruses (seven described species), and the Eurasian Pooideae-infecting dwarf viruses (three described species). Of all known mastrevirus species, Miscanthus streak virus (MiSV), members of which are found in Japan, is the most divergent and is the only one that lies outside these four main lineages. Besides the full-genome sequences of three very closely related MiSV isolates, nothing is presently known about the diversity of what is potentially a fifth major lineage of mastreviruses. Here, we describe a new MiSV-like virus isolated from the grass Eragrostis minor. Curiously, this virus, which we have tentatively named Eragrostis minor streak virus (EMSV), was discovered in Namibia, Southern Africa—almost as far from Japan as it is possible to get within the Old World. An Eragrostis minor plant displaying chlorotic discontinuous streaks running along the major leaf veins (i.e., streak symptoms characteristic of mastrevirus infections) was sampled in the Caprivi region (S18.06447; E21.83855) of Namibia in November 2009. Circular DNA molecules were amplified from a crude total DNA extract using Phi29 DNA polymerase (TempliPhi TM , GE Healthcare, USA) as