A new approach to species delimitation in Septoria - CBS - KNAW

Verkley et al.Notes: The type material from PC studied contains one leaf showingthe typical symptoms, and although only old empty fruitbodieswere observed in it, it is almost certain that these are the productof this well-known and common “Septoria” species. The othermaterial studied here was in much better condition and provedhighly homogeneous in both symptoms and morphology of thesporulating structures, including the collection from Geum rivale,with most conidia observed below 70 µm long. Some authors foundconidia up to about 75 µm long in various European collections(Jørstad 1965, Vanev et al. 1997). In the fresh material from TheNetherlands, conidia were no longer than 65 µm on the host plant,but the isolates obtained from it produced conidia up to 85 µm long.This material is chosen here to epitypify Sphaer. gei because it isgeographically the closest one for which also a culture is available.Several authors have recognised Septoria gei f. immarginatafor material on Geum urbanum with smaller conidia, viz. Radulescuet al. (1973), reporting conidia as continuous, 33–56 × 1.1–1.5 µm(in majority 40–46 × 1.5 µm), and Teterevnikova-Babayan (1983),reporting 20–33 × 1.5 µm. Shin & Sameva (2004) considered thisforma a synonym of S. gei, for which they noted the wide range ofconidial sizes. In Asian collections identified as S. gei the conidiaappear to be longer than in material from elsewhere (Shin & Sameva2004), but the Korean isolates included here are genetically veryclose to the ex-epitype strain CBS 102318, and regarded asconspecific. Sequence analyses of the cultures of Sphaer. geiindicate a close relationship with species such as Sphaer. patriniae(CBS 128653, 129153), from Patrinia scabiosaefolia and P. villosa(Valerianaceae) and Sphaer. cercidis (Quaedvlieg et al. 2013).Sphaerulina hyperici (Roberge ex Desm.) Verkley,Quaedvlieg & Crous, comb. nov. MycoBank MB804476. Fig.45A–D.Basionym: Septoria hyperici Roberge ex Desm., Annls Sci. Nat.,sér. 2, Bot.17: 110. 1842.≡ Phleospora hyperici (Roberge ex Desm.) Westend., Bull. Acad. r.Bruxelles 12 (9): 251. 1845.Description in planta: Symptoms leaf lesions indefinite, usuallystarting to develop from the tip of leaf lamina and progressingtowards the basis, irregular, reddish brown, surrounding leaf tissueoften yellowish; Conidiomata pycnidial, amphigenous, denslydispersed in each lesion, only partly immersed, subglobose toglobose or flask-shaped, brown to black, 55–90(–130) µm diam;ostiolum central, circular, often lifted above the leaf surface,25–35(–50) µm wide, surrounded by concolorous or somewhatdarker cells; conidiomatal wall 10–22 µm thick, composed ofa homogenous tissue of hyaline, angular cells 2–5.5 µm diam,the outermost cells pale brown with slightly thickened walls, theinner cells thin-walled. Conidiogenous cells hyaline, discrete orintegrated in 1–2-septate conidiophores, terminal ones narrowlyto broadly ampulliform, holoblastic, producing a single conidium orproliferating sympodially, 6–8(–10) × 3.5–5 µm. Conidia cylindrical,straight, more often slightly curved or flexuous, broadly rounded atthe apex, narrowing slightly to the truncate base, 1–3(–5)-septate,not or slightly constricted around the septa, hyaline, contents witha few oil-droplets and minute granular material in each cell in theliving state, with oil-droplets and granular contents in the rehydratedstate, 24–55(–63) × 2.5–3.5 µm (living; rehydrated, 1.8–2.8 µmwide). Sexual morph unknown (see notes).Description in vitro: Colonies on OA 4–7 mm diam in 2 wk, with aneven, glabrous, colourless margin; centre and some outgrowingsectors entirely pale luteous to buff, where conidia are formeddirectly on the immersed and superficial mycelium; submarginalarea blackish, due to dark pigmented hyphae and superficialpycnidia, covered by diffuse, white tufty to woolly aerial mycelium;reverse concolourous. Colonies on CMA as on OA. Colonies onMEA 3–7 mm diam in 2 wk (32–40 mm in 6 wk), with an irregular,glabrous margin; a reddish pigment diffusing into the agar; colonyrestricted, the surface cerebriform to irregularly lobed, up to 2 mmhigh, immersed mycelium dark, mostly covered by dense, pure white,woolly aerial mycelium, or salmon to saffron by masses of conidia;reverse cinnamon to brick. Colonies on CHA 3–5 mm diam in 2 wk,with an irregular, glabrous margin; colony restricted, the surfacecerebriform to irregularly lobed, up to 2 mm high, dark but mostlycovered by salmon to saffron conidial masses, and some areas witha dense, pure white, woolly-floccose aerial mycelium; reverse darkbrick.Hosts: Hypericum spp.Material examined: Bulgaria, Camkorije, on leaves of Hypericum quadrangulum,31 Aug. 1907, Fr. Bubák, distributed in Kabát & Bubák, Fungi imperfecti exsicc. 469(PC 0084544). Czech Republic, Bohemia, Bukovina, on leaves of H. perforatum,9 June 1906, J. Kabát, distributed in Kabát & Bubák, Fungi imperfecti exsicc. 421(PC 0084542); same substr., E. Moravia, M. Weisskirchen, Aug. 1941, F. Petrak(PC 0084545). France, loc. unknown, on leaves of H. perforatum, isotype PC0084532; Lighhouse of Libisey near Caen, same substr., June 1841, M. Roberge,PC 0084531; same substr., Bois de Plaisir, 16 July 1935 (Herb. G. Viennot-Bourgin),PC 0084533; same substr., Allier, Gennetines, 5 Apr. 1959, A. Lachmann, PC0084535; Landes, Etang near Seignosse, on H. helodes, 5 Aug. 1964, G. Durrieu,PC 0084536; Seine-et-Marne, Fontainebleau forest, on leaves of H. hirsutum, July1888, Feuilleaubols, PC 0084537, 0084540. Germany, Hessen-Nassau, Dillkreis,Langenaubach, on leaves of H. quadrangulum, 12 July 1931, A. Ludwig, distributedin Sydow, Mycotheca germanica 2570, PC 0084538; Brandenburg, Sadowa, onleaves of H. perforatum, 4 Aug. 1907, P. Sydow, distributed in Sydow, Mycothecagermanica 625, PC 0084543. Netherlands, Prov. Utrecht, Soest, along railroadbetween Lange Duinen and De Zoom, on living leaves of Hypericum sp., 28 July1999, G. Verkley 900, epitype designated here CBS H-21194 “MBT175361”, livingculture ex-epitype CBS 102313. Romania, Moldova, distr. Iaşi, Poeni, on leaves ofH. hirsutum, 1 Aug. 1948, C. Sandu-Ville & I. Rădulescu, distributed in Tr. Săvulescu,Herb. Mycol. Romanicum, fasc. 29, no. 1445, PC 0084534, 0084546. Sweden, E.Götland, Gryt parish, ca. 300 m E.-S.E. of Strömmen, on leaves of H. maculatum,18 July 1947, J.A. Nannfeldt 9386, distributed in S. Lundell & J.A. Nannfeldt, Fungiexsicc. Suecici, praes. Upsal. 1910, PC 0084547.Notes: According to Jørstad (1965), the pycnidia of Sphaer. hypericiare immersed hypophylously, but in most collections investigatedhere they protrude with their ostioli from either side of the leaf inabout equal numbers. Jørstad (1965) further noted that the conidialsizes varied considerably between collections, with extreme valuesranging between 15 and 57 µm for length and 1.5–2.5 µm forwidth of conidia. Vanev et al. (1997) reported conidia 21.5–54 ×2–3.2 µm. In the type specimen, which is rich in conidiomata withprotruding dry spore-masses, conidia are mostly 1–3-septate, 25–50 × 2–2.5 µm, thus in good agreement with the collection V900,which is designated as epitype.Four varieties of Septoria hyperici and a few more Septoriaspecies have been described on species of the genus Hypericum.Most of these taxa have conidia in the size range given herefor Sphaer. hyperici, indicating that these might be conspecific.However, more strains should be isolated from the different speciesof Hypericum and compared with type material of these taxa,before firm conclusions about their status can be drawn. Septoriahypericorum, which was described from H. perforatum with conidiareported 15–35 × 4–6 µm, is likely to belong in Stagonospora oranother related asexual morph. The ex-epitype strain of Sphaer.hyperici CBS 102313 is closely related to strains identified as S.298