Praeclarispora Doilom, W. Dong, K. D. Hyde & C. F. Liao, gen. nov.

Index Fungorum number: IF558142; Facesoffungi number: FoF 09225

Etymology: The generic epithet “Praeclarispora” refers to remarkable-spored.

Saprobic on dead twigs of Artemisia argyi.

Sexual morph: Ascomata black, scattered to gregarious, breaking the epidermis in linear fissures, semi-immersed, becoming erumpent to superficial, subglobose, uni- to multi-loculate, coriaceous, with ostiolate papilla. Peridium unevenly relatively thick, composed of several layers of thick-walled cells of textura angularis, outer layer black, inner layer brown. Hamathecium comprising numerous, filiform, septate, of cellular pseudoparaphyses embedded in a gelatinous matrix. Asci eight-spored, bitunicate, fissitunicate, narrowly obovoid, short pedicellate, apically rounded, with ocular chamber. Ascospores tri- to tetra-seriate, fusiform, curved, tapered toward the acute ends, versicolor, 0–1-septate when immature, becoming brown in median cell and hyaline to pale brown in other cells, middle cell larger than other cells, septate when mature, slightly constricted at the septa, thin- and smooth- walled.

Asexual morph: Undetermined.

Type species: P. artemisiae Doilom, W. Dong, K. D. Hyde and C. F. Liao

Notes: –  Based on a blastn search of NCBIs GenBank, the closest hits using LSU sequence of Praeclarispora artemisiae matches with several genera in Leptosphaeriaceae and has highest similarity to Sphaerellopsis filum (CBS 234.51, identities = 99.18%) and S. paraphysata (CPC 21841, identities = 99.05%), followed by Ochraceocephala foeniculi (CBS 145654, identities =98.83%). The closest hits using SSU sequence are Plenodomus lingam (CBS 260.94, identities = 99.81%), Pl. artemisiae (KUMCC 20-0200A, identities = 99.81%), Pl. biglobosus (CBS 119951, identities 99.81%), and O. foeniculi (CBS 145654, identities 99.71%). ITS sequence matches with published species Pl. hendersoniae (CBS 113702, identities 92.14%), Pl. biglobosus (CBS 119951, identities 89.66%), and O. foeniculi (CBS 145654, identities 87.93%). However, in our multilocus analysis (Figure 1), P. artemisiae forms a sister branch with O. foeniculi with 96% ML and 1.00 BYPP but low MP bootstrap support, and separates from Leptosphaeria, Plenodomus, and Sphaerellopsis. The ITS phylogeny has similar results with the multilocus phylogeny (Supplementary Figure 1); LSU phylogenetic analysis clearly shows Praeclarispora separates from O. foeniculi as a distinct genus (Supplementary Figure 2). A single gene comparison between P. artemisiae and O. foeniculi shows that there are 1.17% (10/854), 0.29% (3/1029), and 13.81% (76/550) nucleotide difference in LSU, SSU, and ITS sequence data, respectively.

Ochraceocephala foeniculi is only known from its hyphomycetous asexual morph, which is characterized by hyaline, loosely or densely branched conidiophores, phialidic conidiogenous cells, and hyaline to yellowish, globose to subglobose conidia, and isolated as plant pathogen from living Foeniculum vulgare (Aiello et al., 2020). Praeclarispora artemisiae is reported herein from only its ascomycetous sexual morph, characterized by black ascomata, narrowly obovoid asci, and fusiform ascospores with a larger, brown, median cell, and isolated as saprobe from decaying twigs of Artemisia argyi. Unfortunately, we could not obtain the asexual morph from the culture for further morphological assessments. Even though we observed them under different conditions as described in Phookamsak et al. (2015) and Senanayake et al. (2020), neither conidia nor conidiomatal structures were produced. Therefore, we believe that it is wise to keep Ochraceocephala and Praeclarispora as separate genera in Leptosphaeriaceae for now. A different scenario may occur with the discovery of similar fungi from both of their asexual and sexual morphs with more fresh sampling.

FIGURE 1 | Phylogenetic tree generated from maximum likelihood analysis (RAxML) based on a combined LSU, SSU, and ITS sequence data. The tree is rooted to Didymella exigua (CBS 183.55). Maximum parsimony and maximum likelihood bootstrap values ≥60% and Bayesian posterior probabilities ≥0.95 (MPBS/MLBS/BYPP) are indicated at the nodes. Ex-epitype, ex-isotype, ex-neotype, ex-type, holotype, and paratype are bolded black, and the new isolates are in red.

FIGURE 2 | Praeclarispora artemisiae (HKAS 112654, holotype). (a–c) Appearance of ascomata on host substrate. (d,e) Vertical sections through ascomata.

(f) Pseudoparaphyses. (g–i) Asci. (j–n) Ascospores. (o) Germinated ascospore. (p) Colony on PDA after 15 days (above and below views). Scale bars: (c) = 250

µm, (d) = 50 µm, (e) = 30 µm, (f,k–m) = 10 µm, (g–j,n,o) = 20 µm.


  • Praeclarispora artemisiae