Ophiobolus clavisporus (J. H.Mill. & Burton) Mlčoch 2024

Mlčoch, Patrik & Matušinsky, Pavel, 2024, Phylogenetic and morphological revision sexual stages of the genus Paraphoma (Phaeosphaeriaceae) and next related species from clade of Ophiobolus-like (Phaeosphaeriaceae), Phytotaxa 663 (4), pp. 184-204 : 199

Ophiobolus clavisporus (J. H.Mill. & Burton) Mlčoch comb. nov. — Fig. 8 .

= Leptosphaeria clavispora J.H. Mill. & Burton 1942

Epitype. BRNM 829162.

MycoBank no: 854611

Sexual morph. Ascoma pseudothecial, subepidermal, globose, 260–340 μm in diam., with small, central, truncateconical ostiole. Ascomal wall composed of 6 to 8 layers of pseudoparenchymatous cells, composed of brown, polygonate cells of textura angularis, (5.5)6–8(8.5) × 4.5–6(6.5) μm, N=20. Asci bitunicate, 8–spored, clavate to cylindrical-clavate, short pedicellate, (71)83–100(120) × (13)14.5–19(19.5) μm, N=10. Ascospores clavate to clavatefusiform, triseriate in ascus, yellowish brown, (7) 8 to 10-septate, third and fourth cells from apex enlarged, constricted at first septum, end cell longer than central cells, with many small lipid drops, without gelationous sheath, appendages or ornamentation, (42)44–61(71) × (6)6.5–8(8.5) μm, Q=5.9–8.7, Q AV =7, N=30. Asexual morph. Undetermined.

Culture characters. Colony on the PDA in culture grown very slow, 10–11 mm in diam. after two weeks at 25 °C. Colony circular to very faintly irregular, greyish to faintly yellowish white, elevation flat to raised, margin entire to faintly curled, lighter than the centre. Conidiomata and conidia undetermined.

Habitat. Dead stems of Eupatorium capillifolium ( Shoemaker 1984) and Artemisia campestris ( Shoemaker 1984; this study).

Distribution. North America ( Shoemaker 1984) and Europe (this study).

Material examined: THE CZECH REPUBLIC: 1. col. P. Mlčoch, Lower Morava Walley, Bzenec, Váté Písky National Natural Monument, xerotermophilic habitat on the sands, 195 m a. s. l., 1. 8. 2020, on the dead stems of Artemisia campestris, GPS : 48.9445569N, 17.2959222E ( BRNM 829162, GenBank no. OR 878084). GERMENY: 2. col. Rehm, Berlin, 12. 7. 1887, on the dead stems of Artemisia campestris (herbarium in Charles University, department of botany, exsiccate nom. nud.), as Leptosphaeria sydowiana Rehm nom. nud.

Notes. Our isolate is identic in sequencing genes with sequences of Leptosphaeria helminthospora Ces. & De Not. (MycoBank accession no. of ITS regions MH 857037.1 and MH 868568.1), but its origin, respectively, correctness of determination relevant isolates not can be verifiable, because they were used to only barcoding analyses ( Vu et al. 2019). Moreover, Saccardo P. A., Traverso G. B. & Trotter A. (1883) states different microscopic characters, including smaller ascospores (20–25 × 5–6 μm). Shoemaker (1984) provides detailed description, including substrate specificity in many collections. However, they correspond to species descripted by J. H. Mill. & Burton. Although Shoemaker (1984) synonymized both species ( Leptosphaeria helminthospora and Leptosphaeria clavispora ) in his theses, it have not to go about the same species. Therefore, here considered only concept by J. H. Mill & Burton and the name of Leptosphaeria helminthospora is need verify. Phylogenetically, our strain is related with Ophiobolus artemisiae (S. Konta, Bulgakov & K.D. Hyde) Wanas. Sequence of O. artemisiae holotype (strain MFLUCC 14-1156, MycoBank accession no. of ITS region MG 520940.1) has 99.0 % similarity with our strain of O. clavisporus in ITS region. Next sequence of O. artemisiae (strain MFLUCC 141156, MycoBank accession no. KT315508.1 see fig. 2) has 98.96 % similarity with our strain and correctness of determination cannot be verified. It is possible, that strain MFLUCC 141156 will be next species. Morphologically, O. artemisiae has largest spores, 80–140 × 3–5 μm, 15–20-septate with slightly constricted at the 8 th or 9 th septum and largest asci, 120–160 × 13–15 μm (Phookamsat et al. 2017), while O. clavisporus has ascospores to 70 μm on the length, over 6 μm on the wide, only to 10-septate, not constricted and asci only to 120 μm on the length.

Figures

FIGURE 8. Ophiobolus clavisporus (BRNM 829162).A: ascomal wall; B–F: ascospores; G–H: asci. Scales: A–F: 10 μm; G–H: 15 μm.