Biology

EMARaV is widespread in Europe, infecting Sorbus aucuparia (European mountain ash, syn. rowan) and inducing chlorotic ringspots, mottle and line pattern on leaves. The virus has been experimentally transmitted by grafting to other Sorbus spp. and to members of the related genera Sorbaronia, Aronia and Amelanchier (Führling and Büttner 1995, Grimova et al. 2015). Graft-inoculated members of the subfamily Maloideae (Amelanchier, Aronia, several different Sorbus spp.) develop symptoms typical of an EMARaV infection. The virus is considered to be naturally transmissible by the eriophyid gall mite Phytoptus pyri (Pagenstecher, syn. Eriophyes pyri, pear leaf blister mite), (Mielke-Ehret et al. 2010), while it can be transmitted mechanically only with difficulty to experimental host plants. It can be detected by virus-specific RT-PCR in Nicotiana rustica and N. benthamiana after rub inoculation of EMARaV-infected Sorbus aucuparia but usually induce no symptoms in these indicator plants and do not establish a stable infection that can be maintained over several virus-passages in these hosts. In other fruit tree species of the family Rosaceae, which are related to rowan, such as Malus domestica and Pyrus communis. the virus has been reported to cause latent infections after successful graft-transmission (Grimova et al. 2015).

EMARaV-infected White-fruited Chinese rowan (S. koehneana) exhibiting chlorotic spots and line pattern.