Phylogeny of three Ramularia species occurring on medicinal plants of the Lamiaceae

Abstract

The plant family Lamiaceae is known for its vast quantity of species and genera with many qualities of medicinal, culinary, and agricultural importance. During a survey exploring ramularia-like taxa associated with leaf spot diseases in northern Iran, several Ramularia isolates were found on symptomatic leaves on different medicinal plants of the Lamiaceae. These isolates were studied by applying a polyphasic approach including morphological and cultural data, and multigene phylogeny (ITS, ACT, TEF1-α, GAPDH, and RPB2). The isolates were grouped in three phylogenetically well-supported newly discovered clades. Of these, R. lamiigena on Lamium album is described as a new species. Furthermore, R. menthae on Mentha arvensis and R. stachydis on Stachys annua, which have previously been reduced to synonymy under R. lamii var. lamii based on morphological data, are reinstated herein based on molecular data. All three species are illustrated, and their morphology and phylogenetic relationships to other Ramularia species are discussed.