Isolation of Oidiodendron maius from Rhododendron and ultrastructural characterization of synthesized mycorrhizas

Abstract

Twelve fungal isolates were obtained from roots of field-grown Rhododendron plants. One of these produced ericoid mycorrhizal roots within 5 days when reassociated with Rhododendron plantlets under aseptic conditions. The organism was identified as Oidiodendron maius. A characteristic feature of this organism was production of conidiophores in both pure culture and in association with root cells of the host. Ultrastructural observations confirmed its mycorrhizal status and showed intracellular hyphae surrounded by an interfacial zone and plasma membrane. Hyphae were found in close association with the host nucleus and cytoplasmic organelles. Pure isolates derived from diverse alternative sources were also tested for mycorrhizal formation with Rhododendron under aseptic conditions. Thus, Pezizella ericae obtained from Calluna vulgaris produced mycorrhizal infections after 10 days of culture, whereas O. maius from Sitka spruce and Oidiodendron griseum from wood pulp failed to form mycorrhizas.

Molecular diversity within and between ericoid endophytes from the Ericaceae and Epacridaceae

“…, Litten and Sigler (Hyphomycetes) (Pearson & Read, 1973 ;Couture et al, 1983 ;Dalpe! et al, 1989 ;Douglas et al, 1989 ;Egger & Sigler, 1993 ;Xaio & Berch, 1995 ;Hambleton & Currah, 1997). The second comprises Oidio-dendron species (Hyphomycetes) and their teleomorphic states Myxotrichum and Byssoascus (Myxotrichaceae) (Couture et al, 1983 ;Dalpe!…”

Molecular diversity of ericoid mycorrhizal endophytes isolated from Woollsia pungens

“…, 1983 ;Dalpe! , 1986 ;Douglas, Heslin & Reid, 1989 ;Perotto et al, 1995Perotto et al, , 1996Hambleton & Currah, 1997) are known to form mycorrhizas with the Ericaceae. The diversity of endophytes of the Ericaceae, however, appears much greater than this ; a range of unidentified sterile mycelia having been isolated and confirmed as mycorrhizal endophytes in laboratory synthesis experiments (Duclos & Fortin, 1983 ;Perotto et al, 1990Perotto et al, , 1995Perotto et al, , 1996.…”

Oidiodendron maius and Scytalidium vaccinii from the mycorrhizas of Ericaceae in northern Finland

“…Within the Ericaceae, 0. maius shows no detectable host specificity and has been identified from roots of many ericaceous plants from alpine and boreal regions of western Canada (Hambleton 1998), from Rhododendron grown in field culture in Ireland (Douglas et al 1989), and from ericoid shrubs in Italy (Perotto et al 1994(Perotto et al , 1996. Our cultures were isolated from each of the three species: Vaccinium vitis-idaea, V. myrtillus, and Empetrum nigrum.…”