Fomitiporellacrystallina sp. nov. (Basidiomycota, Hymenochaetales) from China

Abstract Background Fomitiporella is an important genus of wood-decaying fungi. Many new species were revealed in the last five years, based on morphological characters and molecular data. During a study on the taxonomy of Fomitiporella, two specimens from China were investigated, which have morphological characteristics close to Fomitiporella. After morphological examinations and phylogenetic analyses, a new species was confirmed to be a member of the Fomitiporella clade. New information Fomitiporellacrystallina sp. nov. is described and illustrated as a new species, based on morphological characters and molecular evidence. It has perennial, irregular, pileate basidiocarps, an indistinct subiculum (ultrathin to almost lacking), lack of any kind of setae, has brownish, thick-walled basidiospores and causes a white rot. A molecular study, based on the combined ITS (internal transcribed spacer region) and nrLSU (the large nuclear ribosomal RNA subunit) dataset, supports the new species in Fomitiporella. The differences between the new species and phylogenetically related and morphologically similar species are discussed. A key to species with pileate to effused-reflexed basidiocarps of Fomitiporella is given.


New information
Fomitiporella crystallina sp.nov. is described and illustrated as a new species, based on morphological characters and molecular evidence.It has perennial, irregular, pileate basidiocarps, an indistinct subiculum (ultrathin to almost lacking), lack of any kind of setae, has brownish, thick-walled basidiospores and causes a white rot.A molecular study, based on the combined ITS (internal transcribed spacer region) and nrLSU (the large nuclear ribosomal RNA subunit) dataset, supports the new species in Fomitiporella.The differences between the new species and phylogenetically related and morphologically ‡ §
During a study on the taxonomy of Fomitiporella, two collections from China were investigated.After morphological examinations and phylogenetic analyses, a new species was confirmed to be member of the Fomitiporella clade.In this paper, we describe and illustrate the new species.In addition, an identification key to the worldwide species with pileate to effused-reflexed basidiocarps of Fomitiporella is provided.

Morphology
Studied specimens are deposited in the herbaria of Southwest Forestry University (SWFC) and the Mycological Herbarium of Jiujiang University (MHJU).Microscopic examination follows Dai (2010) and colour terms follow Petersen (1996).Microscopic structures were photographed using a Nikon Digital Sight DS-Fi1 camera.Microscopic measurements were made from slide preparations stained with Cotton Blue and Melzer's reagent.In the text, the following abbreviations were used: KOH = 5% potassium hydroxide, IKI = Melzer's reagent, IKI-= neither amyloid nor dextrinoid, CB = Cotton Blue, CB(+) = cyanophilic after 12 hours stained with Cotton Blue, CB-= acyanophilic, L = mean spore length, W = mean spore width, Q = variation in the ratios of L/W between specimens studied, n = number of spores measured from given number of specimens.

DNA extraction, amplification and sequencing
A CTAB rapid plant genome extraction kit (Aidlab Biotechnologies Co., Ltd., Beijing, China) was used to extract total genomic DNA from dried specimens following the manufacturer's instructions with some modifications (Chen et al. 2016).The DNA was amplified with the primers: ITS4 and ITS5 for ITS (White et al. 1990) and LR0R and LR7 for nrLSU.The PCR protocol for ITS was as follows: initial denaturation at 95°C for 3 min, followed by 35 cycles at 94°C for 40 s, 54°C for 45 s and 72°C for 1 min and a final extension of 72°C for 10 min.
The PCR procedure for nrLSU was as follows: initial denaturation at 94°C for 1 min, followed by 35 cycles at 94°C for 30 s, 50°C for 1 min and 72°C for 1.5 min and a final extension of 72°C for 10 min.The PCR products were purified and sequenced at the Changsha Genomics Institute, China, with the same primers.The resulted ITS and nrLSU sequences were submitted to GenBank (http://www.ncbi.nlm.nih.gov/genbank).
Alignment was manually adjusted to allow maximum alignment and to minimise gaps.Maximum Likelihood (ML) and Bayesian Inference (BI) were employed to perform phylogenetic analysis of the aligned dataset.The two phylogenetic analysis algorithms generated nearly congruent topologies for the dataset and, thus, only the topology from the ML analysis is presented along with statistical values from the ML and BI algorithms (BS not less than 50% and BPP not less than 0.9) at the nodes.The tree was visualised in TreeView 1.6.6 (Page 1996).

Description
Fruiting body (Fig. 2): Basidiocarps perennial, pileate to pendent, hard corky and without odour or taste when fresh, woody hard and medium in weight when dry; pilei irregular, projecting up to 8 cm, 4 cm wide and 3.5 cm thick at base; pileal surface black to dark brown at the margin, narrowly concentrically sulcate, glabrous, with a very hard black crust 1-5 mm thick; margin obtuse.Pore surface greyish-brown when fresh, becoming deep olive when dry; sterile margin yellowish-brown, up to 2 mm wide; pores circular to angular, 5-8 per mm; dissepiments thin, more or less entire to slightly lacerate; tubes woody hard, concolorous with pores, each layer up to 2 mm deep, white mycelial strands present in old tubes.Subiculum very thin to almost lacking.Phylogeny of Fomitiporella inferred from the ITS and nrLSU dataset.Topology is from ML tree and statistical values (ML/BI) are indicated for each node that simultaneously received BS from ML not below 50%, and BPP from BI not below 0.9.

Etymology
Crystallina, referring to the species having abundant crystals.
In conclusion, both morphology and phylogeny support that the specimens, collected from China, are a new species within the genus Fomitiporella.

Table 1 .
Information on the sequences used in this study.Type specimens are shown in bold.Fomitiporella crystallina sp.nov.(Basidiomycota, Hymenochaetales) from ...
Wu et al. (2022)ere included in the phylogenetic analyses and two samples of genus Inocutis were used as outgroups.The final alignment comprised a total of 1667 base pairs (bp) including 804 of ITS and 863 of nrLSU.Two sampled specimens of the new species, Fomitiporella crystallina, formed a well-supported lineage (BS/PP values 98/1.0),indicating that they are phylogenetically distinct from other species in Fig.1.Fomitiporella crystallina has unique morphological characters in Fomitiporella and forms a distinct lineage within the Fomitiporella clade.Morphologically, F. crystallina is similar to F. queenslandica Y.C. Dai & F. Wu in sharing perennial, pileate basidiocarps, a dimitic hyphal structure and the same size of basidiospores (4.1-5 × 3-4 μm), whereas the latter has dimidiate pilei and smaller pores (5-8 per mm;Wu et al. (2022)).Moreover, the presence of the cystidioles and a distinct subiculum in F. queenslandica makes it different from F. crystallina.Phylogenetically, Fomitiporella crystallina is closely related to F. cavicola (Kotl.