Cytospora lumnitzericola Norph., T.C. Wen & K.D. Hyde, in Norphanphoun, Raspé, Jeewon, Wen & Hyde, MycoKeys 38: 104 (2018)
Index Fungorum number: IF 554778; MycoBank number: MB 554778; Facesoffungi number: FoF 04603; Fig. 1
Holotype – MFLU 18-1227
Saprobic on dead stem of unidentified plant. Sexual morph: Stromata indistinct, immersed in bark. Ascostromata 200–250×140–180 µm diam., erumpent in host tissue, scattered, solitary or aggregated, mostly in pairs, uni- or multiloculate, with ostiolar neck. Ostiole 70–100 µm long, central, sometime slanted on substrate, sometime straight, inner layer covered with hyaline, filamentous periphyses. Peridium comprising two layers; inner, hyaline, compressed, cells of textura angularis, outer, brown, cells of textura angularis. Hamathecium comprising cellular, anastomosed paraphyses. Asci 25–30×5–7 μm (x=27×6 μm, n=15), 8-spored, unitunicate, clavate to elongate obovoid, with a J-, refractive apical ring. Ascospores 5–6×1–1.5 μm (x=5.6×1.3 μm, n=20), biseriate, elongated oblong, unicellular, hyaline, smoothwalled. Asexual morph: Norphanphoun et al. (2018).
Culture characters – Colonies on PDA reaching 2.5 cm diameter after 2 days at 25 °C, circular to irregular, medium dense, flat, slightly raised, with edge undulate, fairly fluffy, white from above, light yellow from below; not producing pigments in agar.
Material examined – China, Guangdong Province, Guangzhou City, Baiyun Mountain (23° 09′ 35″ N 113° 17′ 40″ E), on dead stem of unidentified plant, 15 July 2021, I.C. Senanayake, 76 (MHZU 22-0088), living cultures ZHKUCC 22-0154, ZHKUCC 22-0158.
GenBank numbers – ITS: OR164918, OR164919, LSU: OR164960, OR164961, tef1-α: OR166280, OR166281.
Hosts and distribution – Thailand (Phetchaburi Province), on leaf spot of Lumnitzera racemosa (Norphanphoun et al. 2018).
Notes – The combined ITS, LSU and tef1-α gene analysis (Fig. 2) shows that our isolates (ZHKUCC 22-0154, ZHKUCC 22-0158) grouped with the type strain of Cytospora lumnitzericola with ML/BI= 99%/1.00 statistical support. ITS sequences of our isolates reveal one base pair differences with holotype collection and LSU sequences are identical. Our isolates did not sporulate on media and the sexual morph of C. lumnitzericola is unknown. The colony characters of ex-type culture of Cytospora lumnitzericola was described on MEA (Norphanphoun et al. 2018) while our cultures were grown on PDA. However, based on the identical molecular data, we determined that our collection is the sexual morph of C. lumnitzericola. Our collection was obtained from a dead stem as a saprobe while the type collection was from spots of living leaves (Norphanphoun et al. 2018). However, further collections and pathogenicity testing need to confirm the life mode of this fungus.
Figure 1 – Cytospora lumnitzericola (MHZU 22-0088). a Examined material. b, c Ascomata on substrate. d Vertical cross section of ascoma. e Peridium. f–j Asci. k–n Ascospores. k Surface view of colony on PDA. l Reverse view of colony on PDA. Scale bars: d=50 µm, e–n=10 µm
Figure 2 – The best scoring RAxML tree with a final likelihood value of − 25,165.404246 for combined dataset of ITS (609 bp), LSU (876 bp) and tef1-α (663 bp) sequence data. The topology and clade stability of the combined gene analyses was compared to the single gene analyses. The tree is rooted with Diaporthe eres (CBS 160.32). The matrix had 1009 distinct alignment patterns with 45.55% undetermined characters and gaps. Estimated base frequencies were as follows; A =0.253307, C =0.281105, G =0.240277, T =0.225311; substitution rates AC =1.354317, AG =2.316471, AT =1.518768, CG =0.880462, CT =5.395950, GT =1.0; gamma distribution shape parameter α =0.210813. Extype strains are in bold and newly generated sequences are in red. Bootstrap support for ML equal to or greater than 50% and BI equal to or greater than 0.90 are given above the nodes