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

A new approach to species delimitation in SeptoriaHosts: Paris quadrifolia, P. incompleta and Viola palustris.Material examined: Austria, Tirol, Leutaschtal Weidach, on river bank, on livingleaves of Paris quadrifolia, 2 Aug. 2000, G. Verkley 1038, CBS H-21177, livingcultures CBS 109110, 109111; Tirol, Ötztal, Sölden, near Hoch-Sölden, on livingleaves of Viola palustris, 31 July 2000, G. Verkley 1037, CBS H-21152, livingcultures CBS 109108, 109109.Notes: According to the original description, conidia of S. paridisare 20 × 1 µm and aseptate. Vanev et al. (1997) describe theconidia as 18–25 × 1–1.3 µm, Teterevnikova-Babayan (1983),20–25 × 1 µm. As is seen in several other Septoria, the conidiacan reach considerably greater length in culture than on the naturalhost plant. In shape of the conidia the species strongly resemblesS. galeopsidis and S. scabiosicola, as do the cultures, although S.galeopsidis does not produce a red pigment on OA. The material onViola palustris (Violaceae) collected in Tirol was initially identifiedas S. violae-palustris, but based on the DNA sequence analysesof seven loci (Fig. 2) and the agreeing phenotype it is concludedthat the material is conspecific with S. paridis. This is the first reportof this fungus on another host genus than Paris, and also outsidethe Liliaceae. A second Septoria occurring on Paris quadrifolia isS. umbrosa. That species differs from S. paridis by much largerconidia, 30–85 × 3–4.5 µm, which are 5–7-septate.Septoria passifloricola Punith., CMI Descr. PathogenicFungi & Bacteria no. 670. 1980.≡ S. passiflorae Louw, Sci. Bull. Dept. Agric. For. Un. S. Africa 229: 34.1941. Nom. illeg. Art 53 [non Syd., Annls mycol. 37: 408. 1939].Description in vitro: Colonies on OA 12–15 mm diam in 2 wk, withan even, glabrous, buff margin; colonies spreading, immersedmycelium mostly homogeneous orange, but no diffusion ofpigments beyond the margin observed; the surface covered byappressed, greyish white to grey aerial mycelium developing inconcentric areas, beneath which mostly superficial, dark brownto almost black pycnidia or more complex conidiomata develop,releasing pale whitish to dirty greyish droplets of conidial slime;reverse orange to sienna. Colonies on CMA 10–14 mm diam in 2wk, as on OA. Colonies on MEA 5–7(–10) mm diam in 2 wk, with aneven, weakly lobed, black margin, which may be covered by shortfluffy, pure white aerial mycelium; colonies spreading but elevatedat the centre, the surface almost black, with immersed conidiomatalcomplexes soon covered by masses of first pale white, buff, andthen brick conidial slime; the central area later entirely coveredby cerebriform, brick masses of slime; reverse brick to almostvinaceous, and fawn. Colonies on CHA 8–10(–14) mm diam in2 wk, with an even, buff margin covered by a diffuse, felty aerialmycelium; further as on MEA, but surface less elevated, and largelycovered by diffuse, felty, grey-white aerial mycelium; conidialslime as on MEA abundantly produced from similar conidiomatalcomplexes, but more intensely pigmented, deep scarlet; reverseblood colour.Conidiogenous cells (OA) hyaline, discrete, broadlyampulliform to cylindrical, holoblastic, with one or two indistinctpercurrent proliferations (sympodial proliferation not observed),8–14 × 3–6 µm; conidia filiform, hyaline, narrowly rounded at thetop, attenuated to a truncate base, straight to somewhat curved,1–2(–3)-septate, not constricted around the septa, mostly 10–30(–35) × 1.5–2(–2.5) µm.Host: Passiflora edulis.Material examined: Australia, Victoria, Wonthaggi, on Passiflora edulis, Mar. 2011,C. Murdoch, living culture CBS 129431. New Zealand, Auckland, Mt Albert, onliving leaves of P. edulis, 21 Feb. 2000, C. F. Hill MAF LYN-118a, living culture CBS102701.Notes: Priest (2006) provided a description of the fungus on thehost, and discussed the nomenclature. He also mentioned theanonymous reporting of a Septoria state observed in ascosporeisolates from a Mycosphaerella sp. found on fruits lesions, butwhether this truly is the sexual morph of S. passifloricola remainsto be corroborated. The multilocus phylogeny (Fig. 2) providesevidence of a close relationship with S. ekmanniana (CBS 113385,113612) and S. chromolaenae (CBS 113373), and also S. sisyrinchii(CBS 112096) and S. anthurii (CBS 148.41, 346.58).Septoria petroselini (Lib.) Desm., Mem. Soc. Roy. Sci. Lille1843: 97. 1843. Fig. 32.Basionym: Ascochyta petroselini Lib., Pl. Crypt. Arduenna 3: 252.1834.≡ Phleospora petroselini (Lib.) Westend., Bull. Acad. r. Bruxelles 12 (9):252. 1845.Description in planta: Symptoms leaf spots indefinite, without adistinct border, pale brown, visible on both sides in green partsof leaves or barely discoloured petioles. Conidiomata pycnidial,numerous, mostly epiphyllous, semi-immersed, black, mostly80–200 mm diam, with a central, first narrow, later wider opening,releasing pale white cirrhi of conidia; conidiomatal wall composedof one or two layers of brown-walled, angular cells, lined by alayer of hyaline cells. Conidiogenous cells hyaline, discrete,holoblastic, sympodially or percurrently proliferating, ampulliform,6–10 × 3–6 mm. Conidia hyaline, filiform, straight to somewhatflexuous, the upper cell tapered into the obtuse apex, relativelywidely truncate at the base, (1–)3–5(–7) septate, not or onlyindistinctly constricted at the septa, contents granular or withminute oil-droplets around the septa and at the ends, 29–80 ×1.9–2.5 mm (living; rehydrated, 1.2–1.5 mm wide). Sexual morphunknown.Description in vitro (18 °C, near UV) CBS 109521: Colonies onOA 13–16 mm diam in 2 wk, with an even, colourless margin;colonies spreading, immersed mycelium mostly pale ochreous,soon appearing dull green due to the development of dark greenhyphal strands, particularly in a discontinuous submarginalzone; reverse in the centre ochreous to fulvous, surrounded byolivaceous-grey. Conidiomata developing after 5–7 d immersedin the agar or on its surface, most numerous in the centre of thecolony, releasing milky white to rosy-buff conidial slime. Conidiaalso produced directly from mycelium near the centre of thecolony. Colonies on MEA 17–20 mm diam in 2 wk, with an evento somewhat ruffled, buff margin; colonies spreading to restricted,somewhat elevated towards the centre, the surface black withmany stromata developing and releasing milky white droplets ofconidial slime, aerial mycelium diffuse to more dense and low,grey; reverse mostly greenish grey to iron-grey, in the centre withfawn to dark brick haze.Conidiomata and conidiogenous cells as in planta. Conidia(OA) filiform to filiform-cylindrical, straight, flexuous or curved,attenuated gradually to the narrowly rounded to pointed apex,attenuated gradually or more abruptly to the narrowly truncatebase, (0–)3–5(–7)-septate, 30–54(–65) × 2–2.5(–3) µm.www.studiesinmycology.org277