Annulohypoxylon Y. M. Ju, J. D. Rogers & H. M. Hsieh

Rathnayaka, Achala R., Chethana, K. W. Thilini, Manowong, Areerat, Bhagya, Amuhenage T., Win, Hsan, Tun, Zaw L., Mapook, Ausana & Hyde, Kevin D., 2025, Taxonomy, phylogeny, and bioactive potential of Xylariales (Sordariomycetes, Ascomycota) from Thailand: novel species discovery, new host and geographical records, and antibacterial properties, MycoKeys 120, pp. 35-117 : 35-117

Annulohypoxylon Y. M. Ju, J. D. Rogers & H. M. Hsieh , Mycologia 97 (4): 855 (2005)

Notes.

Annulohypoxylon was introduced with A. truncatum as the type species ( Hsieh et al. 2005). Kuhnert et al. (2017) conducted a concise revision of this genus based on molecular phylogeny and chemotaxonomic data, resulting in the identification of several additional species, such as A. massivum , A. violaceopigmentum , A. viridistratum , and A. yungensis . Annulohypoxylon is characterized by effused-pulvinate or pulvinate, glomerate stromata, waxy or carbonaceous tissue immediately beneath the surface and between perithecia, spherical, obovoid, with a carbonaceous stromata layer surrounding individual perithecia. Asci are light- to dark-colored, 8 - spored, cylindrical, stipitate, persistent, with discoid apical ring, amyloid or infrequently inamyloid, while ascospores are light- to dark-colored, ellipsoid or short fusoid, inequilateral, narrowly rounded, or with broadly rounded ends, with a germ slit, perispore dehiscent or indehiscent in 10 % KOH ( Li et al. 2016). Annulohypoxylon species have mainly been recorded in tropical and subtropical regions as saprobes associated with dead dicotyledonous wood and as endophytes in seed plants ( Kuhnert et al. 2017). Hyde et al. (2024) listed 60 species under this genus, while 73 species are included in the Index Fungorum (2025).

Phylogenetic analyses for Annulohypoxylon

Forty-six taxa of Annulohypoxylon were included in the combined data set (ITS, LSU, β-tub, and rpb 2) with Biscogniauxia petrensis ( HKAS 102388 ) as the outgroup taxon. After alignment, the dataset comprised 2832 characters, including gaps (ITS = 585 bp, LSU = 850 bp, β-tub = 380 bp, rpb 2 = 1017 bp). The tree topology of the BI analysis (not shown) was similar to the ML tree. The best-scoring RAxML tree was obtained (Fig. 3 ), with a final likelihood value of - 19758.666775. The matrix had 1149 distinct alignment patterns with 46.81 % undetermined characters or gaps. Estimated base frequencies were as follows: A = 0.248997, C = 0.254092, G = 0.262808, T = 0.234103; substitution rates AC = 1.551284, AG = 4.096946, AT = 1.717695, CG = 1.101636, CT = 7.150044, GT = 1.0; gamma distribution shape parameter α = 0.220052. In BI analyses, the average standard deviation of split frequencies was 0.008 after 3,000,000 generations of runs. The phylogenetic tree topology is similar to that by Kuhnert et al. (2017). Our strains ( MFLUCC 24-0606 , MFLUCC 24-0607 , MFLUCC 24-0608 , MFLUCC 24-0609 , MFLUCC 24-0610 , and MFLUCC 25-0023 ) cluster within Annulohypoxylon .

Figures

Figure 3. Phylogram generated from ML analysis based on the combined dataset of ITS, LSU, β-tub, and rpb 2. The tree is rooted to Biscogniauxia petrensis (HKAS 102388). Bootstrap support values for ML ≥ 70 % and Bayesian posterior probabilities (PP) ≥ 0.90 are noted at the nodes. Strain numbers are noted after the species names. Strains isolated in this study are represented in blue, and type strains are in bold.