First synthesis of ericoid mycorrhizas in the Epacridaceae under axenic conditions

Abstract

The first axenic synthesis of morphologically typical ericoid mycorrhizas of the Epacridaceae has been achieved in micropropagated Epacris impressa Labill. with eight fungi isolated from roots of two epacrid species, E. impressa and Astroloma pinifolium (R.Br.) Benth. Mycorrhizal synthesis has also been achieved between E. impressa and both Hymenoscyphus ericae (Read) Korf and Kernan and Oidiodendron griseum Robak, recognized endophytes of Ericaceae, suggesting that the endophytes of the Epacridaceae and Ericaceae are capable of cross-infection. Infection rate of epidermal cells on hair roots varied from 3-77 % infection and the density of hyphal coils varied widely. This synthesis makes possible studies of the roles of these endophytes in the Epacridaceae and comparison with their roles in the Ericaceae.

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

“…This study shows for the first time the relationships in the ITS region between Northern Hemisphere endophytes, eight Victorian endophytes and one nonmycorrhizal isolate (McLean et al, 1998). On the basis of their high within-cluster ( 96%) sequence similarity, E4-1-2, E4-5-5, E3-1, AP-3 and AP-8 could be a single taxon or at least closely related species.…”

“…However, most have not been confirmed as mycorrhizal on Epacridaceae, although a few have formed ericoid mycorrhizal pelotons on Ericaceae (Reed, 1989 ;Liu et al, 1998). The recent confirmation of some Victorian epacrid isolates as being capable of forming morphologically typical ericoid mycorrhiza in Epacridaceae (McLean et al, 1998) now enables them to be compared by modern molecular methods with some known mycorrhizal fungi of the Ericaceae.…”

“…mycorrhizal endophytes of the Ericaeae produced morphologically typical ericoid mycorrhizal morphology with axenic Epacris impressa Labill. (Epacridaceae) (McLean et al, 1998) and by earlier reports of infection of Vaccinium species (Ericaceae) by fungi isolated from epacrid roots (Reed, 1989 ;Liu et al, 1998).…”

“…Nine of these isolated fungi from seven of the most numerous morphological groups were chosen because they had previously been tested for the ability to form typical ericoid mycorrhizal pelotons in E. impressa (McLean et al, 1998).…”

“…Isolates selected for sequencing were : H. ericae 100, eight mycorrhizal endophytes shown previously to form typical ericoid mycorrhizal morphology in E. impressa (E1-9, E2-16, E3-1, E4-1-2, E4-5-5, AP-1, AP-3 and AP-8) and one non-mycorrhizal isolate, E2-1 (McLean et al, 1998). The rDNA ITS region was amplified with primers ITS5 and ITS4 (White et al, 1990).…”