A phylogenetic and taxonomic study on Steccherinum (Polyporales, Basidiomycota): Focusing on three new Steccherinum species from southern China

Abstract

The wood-inhabiting fungi play an integral role in wood degradation and the cycle of matter in the ecological system. They are considered as the “key player” in wood decomposition, because of their ability to produce all kinds of enzymes that break down woody lignin, cellulose and hemicellulose. In the present study, three new wood-inhabiting fungal species, Steccherinum fissurutum, S. punctatum and S. subtropicum spp. nov., collected from southern China, are proposed based on a combination of morphological features and molecular evidence. Steccherinum fissurutum is characterized by the resupinate, subceraceous basidiomata with cracked hymenophore, a monomitic hyphal system with clamped generative hyphae and cylindrical basidiospores; S. punctatum is characterized by the annual, punctate basidiomata with leathery hymenophore, cylindrical, strongly encrusted cystidia and ellipsoid basidiospores (3.6–4.5 ×2.6–3.4 µm); S. subtropicum is characterized by its effuse-reflexed basidiomata, a odontioid hymenophore with pink to lilac hymenial surface and ellipsoid basidiospores measuring as (2.8–3.4 × 2.0–2.7 µm). Sequences of ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. The ITS+nLSU analysis of the family Steccherinaceae indicated that the three new species clustered into the genus Steccherinum. Based on further analysis of ITS+nLSU dataset, the phylogenetic analysis confirmed that S. subtropicum was sister to S. enuispinum; S. fissurutum formed a monophyletic lineage; S. punctatum grouped with a clade comprised S. straminellum and S. ciliolatum.

Notes of Five Wood-Decaying Fungi from Juwangsan National Park in Korea

“…Many of its species have been misclassified because of morphological similarities between distinct groups. Currently, species delimitation and reclassification of wood-decaying fungi are being conducted owing to the development of DNA-based identification [ 37 , 52 , 60 , 70 , 72 , 73 ]. Consequently, many species have been reclassified into other genera and families.…”

Untitled

“…However, R. tropica differs in R. purpurascens by its greyish to pinkish buff pore surface, larger angular pores (3-4 per mm) and longer cylindrical to subfusiform basidiospores (8.3-10 × 2.5-3 μm) (Cui 2013, Liu et al 2023a); R. subtropica is distinguished from R. purpurascens by its larger angular pores (3-4 per mm) and longer cylindrical to subfusiform basidiospores (7-8.4 × 2.6-3.3 μm) (Liu et al 2023b) (Liu & Cui 2021, Dong et al 2022, Liu et al 2023c). However, S. fragile is distinguished from S. wumengshanens by having the salmon to peach pore surface and smaller clavate basidia (13-14 × 4-4.5 µm) (Liu & Cui 2021); S. hirsutum is distinguished from S. wumengshanens by having the stipitate, scarlet to red basidiomata and larger conical aculei (2-4 per mm) (Dong et al 2022); S. incrustans differs from S. wumengshanens by having buff yellow to clay buff pore surface and smaller skeletocystidia (15-35 × 5-10 µm) (Dong et al 2023); S. punctatum is separated from S. wumengshanens by having the shorter skeletocystidia (36-47 × 7.5-12 µm) and longer basidia (23-27 × 5.5-7.5 µm) (Liu et al 2023c).…”

“…Johans., Junghuhnia Corda and Steccherinum (Polyporales, Basidiomycota) grouped together and Steccherinum was shown to contain both hydnoid and poroid species (Miettinen et al 2012). The genus Steccherinum is the largest genus in the family Steccherinaceae with a worldwide distribution (Dong et al 2022(Dong et al , 2023, and recently based on results of molecular phylogenetic analyses, some Steccherinum species have been transferred to other genera (Westphalen et al 2021, Liu et al 2023c.…”