Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Detection of Olpidium brassicae by a baiting plant method from field soils in Japan, and their transmissibility of tulip mild mottle mosaic virus.

Abstract

The distribution of O. brassicae in Japan was examined using a baiting plant method and the abilities of O. brassicae isolates to transmit tulip mild mottle mosaic virus (TMMMV) were evaluated. Seventy-three soil samples were collected from different areas in Japan. The soil samples, or root debris from selected sampling points, were inoculated onto the surface of soil in pots, to which cowpea (Vigna unguiculata 'Kurodane Sanjaku'), oriental melon (Cucumis melo 'Ginsen'), lettuce (Lactuca sativa 'Cisco'), tobacco (Nicotiana tabacum 'White Barley'), oat (Avena fatua 'Hay Oat') or cabbage (Brassica oleracea 'Shutoku') was planted as bait. O. brassicae was detected in the roots of at least one of these baiting plants grown in the 58 pots. The most successful plants in the recovery and propagation of O. brassicae from the soil were cowpea and oriental melon. However, oat, cabbage and tobacco were not good baiting plants because only a few O. brassicae could be recovered and propagated in these plants. All isolates trapped on cowpea or oriental melon propagated well, but some isolates differed in host specificity to lettuce and cabbage. Forty-nine isolates in total, including 11 single sporangial isolates, obtained from the soil or root debris, were tested for their transmissibility of TMMMV. Nine isolates failed to transmit TMMMV, while 40 isolates succeeded in transmitting the virus from infected tulip to healthy tulip. The results show that O. brassicae inhabits many field soils in Japan, and the majority of O. brassicae isolates can transmit TMMMV.