Revisiting the phylogeny and taxonomy of the genus Sidera (Hymenochaetales, Basidiomycota) with particular emphasis on S.vulgaris

Abstract

The genus Sidera (Hymenochaetales, Basidiomycota) comprises white-rot, mono- or dimitic fungi with poroid or hydnoid hymenophore. It has a worldwide distribution albeit with fewer species present in the Southern Hemisphere. Although recent studies revealed the existence of several new Sidera species, there are still taxonomic inconsistencies and obscure phylogenetic relationships amongst certain taxa of the genus. In this work, a large number of Sidera collections were used to obtain an updated phylogeny, based on ITS and 28S rDNA sequences by including new material from Mediterranean Europe. The monophyly of the genus was strongly supported and all species with poroid hymenophore formed a highly-supported lineage with two major subclades. In total, 23 putative species were recognised. Amongst those, five are considered to possibly represent entities new to science, but further work is required since they are represented by single specimens or environmental sequences. Examined collections originally named S.lenis from southern Europe were grouped within S.vulgaris. Similarly, several collections under various names were hereby identified as S.vulgaris, including those of the recently described species S.tibetica. Furthermore, a critical discussion (based on morphoanatomical findings) is made on the key features that could be used to distinguish S.lenis from S.vulgaris.

Keywords: Basidiomycetes; Mediterranean Europe; biodiversity; fungal phylogeny; mushroom; white-rot fungi.

Figure 1.

S.vulgaris specimen in situ (ΑCAM 2013-0017). Scale bar: 5 cm (left); 2 cm (right).

Figure 2.

Micromorphological features of S.vulgaris; scale bar 5 μm [except of f and g 10 μm] a basidiospores (all specimens) b basidia (ACAM 2013-0017, ACAM DD2559, HUBO 7745, HUBO 8296, HUBO 8465, SALA-Fungi 3752) c hymenium with basidia and basidioles (HUBO 8465) d branched and unbranched cystidioles bearing crystals at apex (asterocystidia) (ACAM DD2559, SALA-Fungi 3752, SALA-Fungi 4111) e hymenial cystidioles (ACAM DD2559, HUBO 8296, SALA-Fungi 3749) f hyphae of the subiculum with dominating skeletals (ACAM 2013-0017) g dissepiment edges with skeletal and generative hyphal ends (HUBO 7745) h details of the rosette-like crystal clusters from tramal hyphae (HUBO 7745) i capitate ends of generative hyphae from dissepiments and hymenium (with mucous droplets) (HUBO 8296, SALA-Fungi 3749, SALA-Fungi 3752) j skeletal hyphae from dissepiments with swellings (ACAM 2013-0017, HUBO 7745, SALA-Fungi 3752, SALA-Fungi 4111).

Figure 3.

Phylogenetic relationships within the genus Sidera inferred by using ML analysis on the ITS sequence dataset. ML BS ≥ 65% and BPP ≥ 0.95 are appended to nodes; asterisk denotes 100% ML BS and/or 1.00 BBP. Specimens studied are followed by their voucher code and geographic origin. Sequences determined in the present study appear in bold, while those representing type material are underlined. The phylogram is rooted with Skvortzoviafurfuracea and Skvortzoviafurfurella. The scale bar indicates 0.1 expected change per site per branch.

Figure 4.

Phylogenetic relationships within the genus Sidera inferred by using ML analysis on the concatenated ITS and 28S rDNA sequence dataset. ML BS ≥ 65% and BPP ≥ 0.95 are appended to nodes; asterisk denotes 100% ML BS and/or 1.00 BBP. Specimens studied are followed by their voucher code and geographic origin. Sequences determined in the present study appear in bold, while those representing type material are underlined. The phylogram is rooted with Skvortzoviafurfuracea and Skvortzoviafurfurella. The scale bar indicates 0.1 expected change per site per branch.