Morphological and phylogenetic evaluation of a new species of Rhodoveronaea (Rhamphoriaceae, Rhamphoriales) associated with Quercusfabrei (Fagales) in Yunnan Province, China

Abstract

Background: During an extensive mycological exploration of Fagales-associated mycoflora within the biodiverse landscapes of Yunnan Province, China, we discovered a new saprotrophic fungal species. Based on its unique morphological characteristics and phylogenetic analyses of combined LSU, ITS, SSU, tef1-α and rpb2 sequences, we established Rhodoveronaeaquerci as a new member of the genus Rhodoveronaea, which was collected from Quercusfabrei colonising terrestrial habitats.

New information: Rhodoveronaeaquerci is currently only known from its asexual form, which is a morphologically distinct hyphomycete fungus. The distinguishing characteristics of R.querci are straight or slightly flexuous, septate and unbranched conidiophores, terminally, integrated, apically protuberant, recurved conidiogenous cells with conspicuous conidiogenous loci and ellipsoidal to narrowly-obovoid, mostly 1-septate, slightly constricted at the central septum, guttulate, conidia with a flat basal scar. Rhodoveronaeaquerci and R.hainanensis are highly similar in the size and shape of their conidiophores and conidia, but they can be distinguished by other morphological characteristics and by genetic differences. Rhodoveronaea species are widely distributed in Europe and Asia and recent studies revealed several new Rhodoveronaea species from China.

Keywords: Fagaceae; asexual morph; new species; phylogeny; taxonomy.

Figure 1.

Map of the northern urban area of Kunming City with altitude information.

Figure 2.

Rhodoveronaeaquerci (HKAS 145561, holotype). a Host substrate; b, c Colonies on the substrate; d, e Conidiophores and conidiogenous cells bearing conidia; f, g Conidiogenous cells bearing conidia. Note the percurrent proliferation of conidiophores from cut-ends in e-g; h-m Conidia; n Germinated conidium; o, p Upper and lower view of culture on PDA media after incubation for 60 days. Scale bars: d–e, g, n = 30 μm, f = 20 μm, h–m = 10 μm.

Figure 3.

RAxML tree, based on combined LSU, ITS, SSU, tef1-α and rpb2 dataset analyses. Bootstrap support values for Maximum Likelihood (ML, first value) equal to or greater than 60% and Bayesian posterior probabilities (BPP, second value) equal to or greater than 0.90 are given at the nodes. Ex-type strains are in bold; the newly-generated isolates are in red.