16 Oct Medeolaria

Medeolaria Thaxt., Proc. Amer. Acad. Arts & Sci. 57(17): 432 (1922)

The genus Medeolaria belongs to the family Medeolariaceae (Medeolariales, Leotiomycetes, Ascomycota). Medeolaria was introduced by Thaxter (1921) and typified with Medeolaria farlowii. Medeolaria species are pathogens of Medeola virginiana (Liliaceae). Currently, the known distribution of this genus is only from America.

Classification – Leotiomycetes, Medeolariales, Medeolariaceae

Type species – Medeolaria farlowii Thaxt., Proc. Amer. Acad. Arts & Sci. 57(17): 432 (1922)

Distribution –America

Disease symptoms –This fungus causes gall-like deformations on thickened, hypertrophic parts below leaf whorls of herbaceous stems of the host tissue, in autumn. However, they are present not only in stem lesions of the host plant but in uninfected leaves, stems, and rhizomes (Pfister et al 2013). Pfister et al. (2013) also showed the long-term perpetuation of the fungus in populations of the plant. They suggested the fungus remains a systemic infection of vegetative plant parts and when the plant reproduces clonally, this infection is carried in populations of the host plant (Pfister et al 2013).

Hosts – Magnolia spp.

Morphological based identification and diversity

This genus contains only a single species, Medeolaria farlowii Thaxter (1922), described from material collected from Magnolia. It produces erumpent, indefinite apothecia with a palisade layer of asci and paraphyses. An excipulum is absent or is a very thin layer. The hymenium layer forms fusiform swellings below and/or between the shortened internodes of the host plant. Ascospores are large, fusiform to navicular, with a dark, striate outer wall. The asexual morph of this fungus is unknown (Korf 1973; Pfister and LoBuglio 2009; Ekanayaka et al 2017).

Molecular based identification and diversity

The first stable taxonomic placement for this genus was provided by Korf (1973) under the family Medeolariaceae, order Medeolariales within Leotiomycetes, according to its morphology. Recent phylogenetic studies (LoBuglio and Pfister 2010; Pfister et al 2013; Ekanayaka et al. 2017) confirmed its phylogenetic relationship with Leotiomycetes (Fig. 10), but the phylogenetic position within the class is unresolved.

Recommended genetic markers (genus level) – ITS

Recommended genetic markers (species level) – ITS

ITS is the best single genetic marker for the genus Medeolaria (Pfister et al 2013). Pfister et al. (2013) provided primers, designed to specifically amplify ITS rDNA regions of Medeolaria farlowii.

The accepted number of species: One species

References: Korf 1973; LoBuglio and Pfister 2010; Pfister et al. 2013(morphology, phylogeny).