Root colonization ofLupinus latifoliusAgardh. andPinus contortaDougl. byPhialocephala fortiniiWang & Wilcox

Abstract

SUMMARYRoot colonization patterns were studied after Phialocephala fortinii w as inoculated on Lupinus tatifolius (broadleafed lupin), a nitrogen-fixing legume, and Pinus contorta (lodgepole pine). The fungus colonized epidermal and cortical cells in the root hair zone on ultimate pine roots, as well as cortical and epidermal cells of primary roots of both hosts. Fungal colonization was inter-and intracellular with sclerotia forming in cells of both hosts. Labyrinthine tissue, a type of fungal differentiation that occurs in the Hartig net of ectomycorrhizas, formed sporadically on pine roots. Similar colonization has been observed on conifers and many other plants, but this report is the first showing that a single fungus can form such structures on both pine and lupin.

Dark septate endophytes: a review of facultative biotrophic root‐colonizing fungi

“…The pattern of DSE colonization is similar in roots of different plant species that are otherwise mainly considered as arbuscular, ericoid, orchid or ectomycorrhizal (see Peyronel, 1924 ;Va$ re, Vestberg & Eurola, 1992 ;Currah, Tsuneda & Murakami, 1993 ;O'Dell et al, 1993 ;Stoyke & Currah, 1993). Plants that do not form mycorrhizas also have similar fungal structures when colonized by DSE (Haselwandter & Read, 1982 ;Ca!…”

“…We recognize that an unknown number of fungal taxa (anamorphic and\or teleomorphic) are involved, and that a considerable functional and ecological overlap might exist between soil fungi, saprotrophic rhizoplane-inhabiting fungi, strictly pathogenic fungi, mycorrhizal fungi and fungal endophytes. Because Richard & Fortin (1974) reviewed the Currah et al (1987) ; Stoyke & Currah (1991) ; Stoyke et al (1992) ; Va$ re et al (1992) Pseudomycorrhizal Melin (1923 ; Thomas (1943) ; Robertson (1954) ; Kowalski (1970 ; ; Wang & Wilcox (1985) ; O'Dell et al (1993) literature on MRA, we only cover briefly the earlier work, and emphasize what has been published since.…”

“…The morphology of DSE-colonized roots had been reported to resemble ectomycorrhizas (Wilcox & Wang, 1987 b ;O'Dell et al 1993), ectendomycorrhizas Wang & Wilcox, 1985 ;, and pseudomycorrhizas (Wang & Wilcox, 1985). In some cases the structures in the colonized root suggested a pathogenic association (Wang & Wilcox, 1985 ;.…”

“…Melin (1922Melin ( , 1923Melin ( , 1925 reported that host roots were intracellularly colonized and that neither Hartig net nor mantle was present. Morphological studies of colonized roots have since revealed, however, that DSE occasionally develop a partial Hartig net and a thin mantle only a few cell layers thick (O'Dell, Massicotte & Trappe, 1993 ;Fernando & Currah, 1996). Richard & Fortin (1974) pointed out that DSE fungi are widely distributed in coniferous boreal forests.…”

“…Morphological structures of DSE-colonized roots do not fall clearly into any previously described category of mycorrhizal, parasitic or pathogenic associations. The terms consequently introduced to describe the patterns of this root-fungus association were : ' dark septate ' (Read & Haselwandter, 1981) or ' septate ' endophytes (O'Dell et al, 1993).…”