Pteridopassalora nephrolepidicola (Crous & R.G. Shivas) C. Nakash. & Crous, in Chen et al., Stud. Mycol. 101: 550 (2022)

Index Fungorum Number: IF 841683; Facesoffungi Number: FoF 15740

Basionym – Pseudocercospora nephrolepidicola Crous & R.G. Shivas, Persoonia 25: 139. 2010.

Etymology – Named after the host from which it was collected, Nephrolepis (Lomariopsidaceae).

Leaf spots amphigenous, medium brown, with indistinct margins, 2–12 mm diam. Asexual morph: Conidiomata pale to medium brown, amphigenous, fasciculate, arising from a well-developed subepidermal, medium brown stroma, up to 150 µm wide, and 50 µm high. Mycelium consists of smooth, septate, brown, branched, 2–3 µm diam hyphae. Conidiophores subcylindrical, medium brown, smooth, unbranched or branched below, irregularly geniculate-sinuous, in loosely aggregated fascicles, or separate on superficial mycelium, 1–4-septate, 25–45(–90) × 2.5–3(–3.5) µm. Conidiogenous cells terminal on conidiophore, integrated, subcylindrical, pale brown, smooth, proliferating 1–2 times percurrently near apex, 15–25(–40) × (2–)2.5(–3) µm. Conidia medium brown, smooth, guttulate, subcylindrical, straight to irregularly flexuous, apex obtusely rounded, base truncate, 3–6(–9)-septate, (40–)50–60(–95) × (2.5–)3.5(–4) µm; hila not thickened nor darkened. Sexual morph: Ascomata globose, erumpent, brown, up to 80 µm diam, with a central ostiole. Asci subcylindrical to narrowly obovoid, 35–50 × 8–10 µm. Ascospores fusoid-ellipsoidal, widest in middle of the apical cell, tapering towards both ends, apex acutely rounded, constricted at septum, 9–11 × 2.5–3.5 µm.

Culture characteristics — (in the dark, 25 °C, after 2 wk): Colonies spreading, erumpent, with folded surfaces and even, lobate margins, reaching up to 15 mm diam. On potato-dextrose agar surface smoke-grey with patches of grey-olivaceous, iron-grey in reverse; on malt extract agar pale olivaceous-grey (surface), iron-grey in reverse; on oatmeal agar olivaceous-grey with patches of pale olivaceous-grey.

Typus – Australia, Queensland, Brisbane Botanical Garden, on fronds of Nephrolepis falcata (Nephrolepidaceae), 14 Jul. 2009, P.W. Crous & R.G. Shivas (holotype CBS H-20492, cultures ex-type CBS 128211 = CPC 17049, CPC 17050).

GenBank Accession Numbers – CPC 17049 – ITS: HQ599590, LSU – HQ599591

Notes — There are several specimens of Pseudocercospora spp. on Nephrolepis in BRIP, which cannot easily be identified using morphology alone. Pseudocercospora nephrolepidicola is morphologically and phylogenetically distinct from P. nephrolepidis (on Nephrolepis cordifolia (as N. auriculata) in Taiwan; conidia subcylindrical, (32–)67–101(–113) × 2–3 μm, 2–9 septate; CBS 119121), in that its conidia are shorter and wider. Furthermore, Pseudocercospora phyllitidis, which was described from leaves of Nephrolepis sp. from Florida, has smaller stromata (up to 75 µm diam) with straight to mildly curved obclavate conidia, 20–80 × 2–3.5 µm, than the Australian specimen. A megablast search of NCBIs GenBank nucleotide database using the LSU sequence retrieved as closest sisters Mycosphaerella quasiparkii (GenBank EU882143; Identities = 807/808 (99 %), Gaps = 0/808 (0 %)), Rosenscheldiella brachyglottidis (GenBank GQ355334; Identities = 874/886 (99 %), Gaps = 0/886 (0 %)), Mycosphaerella swartii (GenBank DQ923536; Identities = 865/888 (98 %), Gaps = 3/888 (0 %)) and Pseudocercospora vitis (GenBank GU214483; Identities = 864/889 (98 %), Gaps = 5/889 (0 %)). A megablast with the ITS sequence revealed high identity to ‘Mycosphaerella sp. DeNo’ (GenBank HM189290; Identities = 481/482 (99 %), Gaps = 0/482 (0 %)), M. quasiparkii (GenBank EU882127; Identities = 573/597 (96 %), Gaps = 17/597 (2 %)) and Pseudocercospora schizolobii (GenBank GQ852765; Identities = 571/610 (94 %), Gaps = 28/610 (4 %)).