Ecological, morphological and phylogenetic survey of Fomes fomentarius and F. inzengae (Agaricomycetes, Polyporaceae) co-occurring in the same geographic area in Central Europe

Abstract

The phenomenon of cryptic species is widespread among various fungal lineages. Fomes inzengae (Ces. & De Not.) Cooke has been recently recognized as a South European kin of wood-decay basidiomycete F. fomentarius (L.) Fr. due to the problematic morphological identification of both species, their taxonomic status has been disputed. The aim of this research is to examine the distribution, host preferences, morphological characters, and phylogenetic relationships between F. fomentarius and F. inzengae in the South Moravian region in Czechia (Central Europe), where both species occur sympatrically. The results revealed the ecological preferences of Fomes spp. along an altitudinal gradient, while F. inzengae is a lowland taxon, F. fomentarius dominates at higher altitudes in forests with abundant Fagus sylvatica. The main contact zone of the two taxa is located in the upper-colline vegetation belt (elevation ca. 400‒550 m a.s.l.). The morphological analysis revealed that the basidiospore size, the width of skeletal hyphae in basidiomes, and the linear density of pores of both taxa are almost identical and can not be used for the identification of the two species. Multigene sequence analyses of ITS, LSU, RPB1, RPB2, and TEF1 markers confirmed that F. fomentarius and F. inzengae are phylogenetically distinct species. The relationship of F. inzengae and F. fomentarius to Globifomes graveolens and Hexagonia spp. is discussed.

Characterization of Fomes fomentarius s.s. and F. inzengae in Belgian Beech Forests

“…It differs from F. fomentarius s.s. in its hosts range, but also in growth characteristics and volatile compounds [21]. F. fomentarius s.s. and F. inzengae also show micro-morphological differences, but these are not easily identifiable in the field [24].…”

“…As part of a phylogenetic study of a large number of ITS sequences from isolates from various geographical origins, two of these sublineages were renamed: F. fomentarius s.s. corresponds to sublineage A2 while F. inzengae corresponds to sublineage B2 [21]. Although they have different micro-morphological characteristics, distinguishing lineages A and B on a visual basis is difficult [24]. Polymorphisms in the ITS sequence make it possible to identify them, but sequencing the ITS zone requires the isolation of a pure strain if specific PCR primers are not available, which is time-consuming and not always possible, particularly when the fungus is in a latent form in the wood.…”

“…To our knowledge, this is the first report of this species in Belgium. This fungus has been reported in Europe, notably in England, Italy, Latvia, Slovakia and Slovenia [46], Spain [47] and the Czech Republic [24]. It is capable of infecting various hardwood species, but rarely infects beech trees, unlike F. fomentarius s.s. which is prevalent on beeches [21].…”