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

Verkley et al.Septoria galeopsidis Westend., Bull. Acad. r. Belg., Cl. Sci.,Sér. 2, 2: 577. 1857. Fig. 20.= Ascochyta galeopsidis Lasch in Rabenh., Herb. Myc. I, 1058. 1846 [nom.nud.].= Septoria cotylea Pat. & Har., Bull. Soc. Mycol. France 21: 85. 1905.Description in planta: Symptoms leaf spots irregular or angular,becoming dark brown, in yellow parts of the leaf lamina.Conidiomata pycnidial, hypophyllous, often numerous in eachleaf spot, globose to subglobose, dark brown, almost completelyimmersed, 75–100(–130) µm diam; ostiolum central, initiallycircular, 15–25 µm wide, surrounding cells somewhat darker;conidiomatal wall 10–22 µm thick, composed of textura angulariswithout distinctly differentiated layers, the cells 3–8 µm diam,the outer cells with brown, somewhat thickened walls, the innercells with hyaline and thinner walls. Conidiogenous cells discrete,sometimes integrated into 1–2-septate conidiophores, hyaline,narrowly or broadly ampulliform with a relatively narrow neck,holoblastic, proliferating percurrently with indistinct annellations,and also sympodially, 6–12(–15) × 3.5–5(–6) µm. Conidia filiform,straight or slightly curved, sometimes flexuous, with a rounded orsomewhat pointed apex, attenuated towards the narrowly truncatebase, (0–)3(–5)-septate, not constricted around the septa, hyaline,contents with several minute oil-droplets and granular material ineach cell in the living state, with inconspicuous oil-droplets andgranular contents in the rehydrated state, 20.5–44 × 1.5–2.5 µm(living; rehydrated, 1–2 µm wide). Sexual morph unknown.Description in vitro: Colonies on OA 7–13 mm diam in 2 wk (35–43mm in 6 wk), with an even, glabrous, colourless margin; coloniesalmost plane, immersed mycelium homogeneously olivaceousblackto greenish black (also near the margin); aerial myceliumscanty, woolly-floccose, white or greyish; superficial pycnidialconidiomata scanty, scattered over the central aerea, releasingmilky white droplets of conidial slime; reverse dark slate blue toblack. Colonies on CMA 7–13 mm diam in 2 wk (33–37 mm in 6wk), as on OA, but concentration of conidiomatal development inelevated pustules on the elsewhere flat colony. Colonies on MEA6–11 mm diam in 2 wk (33–39(–46) mm in 6 wk), the margin even,later undulating, buff, narrow and glabrous; colonies hemispherical,often irregularly pustulate or with columnar outgrowths up to 5mm high, immersed mycelium olivaceous-black to black, mostlycovered by a dense mat of finely velted, greyish aerial mycelium;faster growing, glabrous sectors with buff immersed mycelium mayappear after several weeks; conidiomata starting to develop onthe (dark) colony surface, tardily sporulating with whitish to fleshdroplets of conidial slime; reverse brown-vinaceous or olivaceousblack.Colonies on CHA 5–10(–15) mm diam in 2 wk (20–29 mmin 6 wk), with an even, glabrous to nearly so, buff margin; coloniesirregularly pustulate, immersed mycelium olivaceous-black, mostlycovered by a dense but appressed mat of woolly-floccose, greyaerial mycelium, in some slightly faster growing sectors pure white;scattered but scarce superficial conidiomata releasing pale fleshdroplets of conidial slime; reverse blood colour to black.Conidiomata pycnidial and similar as in planta, 100–150 µmdiam, or merged into larger complexes especially on the agarsurface, dark brown, up to 200 µm diam; ostiolum as in planta,or absent. Conidiogenous cells hyaline, ampuliform, or elongatedampulliform to cylindrical, with a distinct neck, holoblastic,proliferating percurrently with indistinct scars (annellations), orsympodially, 8–13(–15) × 3–4.5(–5) µm. Conidia cylindrical,straight or slightly curved, tapering to a rounded or somewhatpointed apex, lower part slightly or more clearly attenuated into abroad truncate base, (0–)1–3(–5)-septate, not constricted aroundthe septa, hyaline, with several oil-droplets and minute granularmaterial in each cell, (37–)50–65 (–70) × 2–2.5 µm.Hosts: Galeopsis angustifolia, G. ladanum, G. pubescens, G.speciosa and G. tetrahit.Material examined: Belgium, in the vicinity of Mons, on leaves of Galeopsis tetrahit,R. P. Clém. Dumont, distributed in Westendorp & Wallays, Herb. crypt. Belge, Fasc.23-24, no 1134, isotype BR-MYCO 158116-06. Czech Republic, Moravia, Mikulov,on living leaves of Galeopsis sp., 15 Sep. 2008, G. Verkley 6003, CBS H-21256,living cultures CBS 123744, 123749; same substr., date, Moravia, Milovice, forestMilovika stran, G. Verkley 6006, CBS H-21254, living cultures CBS 123745, 123746.France, Corrèze, Prât Alleyrat, on living leaves of G. tetrahit, 25 July 1976, H.A. vander Aa 5344, CBS H-18099; loc. unknown, isol. C. Killian ex Galeopsis sp., livingculture CBS 191.26. Netherlands, prov. Noord-Brabant, Cromvoirt, on living leavesof G. tetrahit, 2 June 1963, H.A. van der Aa s.n., CBS H-18097; prov. Gelderland,Putten, on living leaves of G. tetrahit, 8 Aug. 1984, G. de Hoog s.n., CBS H-18100;prov. Utrecht, Soest, on living leaves of G. tetrahit, 4 Aug. 1999, G. Verkley 902, CBSH-21195, living culture CBS 102314; prov. Limburg, St. Jansberg near Plasmolen,on living leaves of G. tetrahit, 9 Sep. 1999, G. Verkley 934, epitype designatedhere CBS H-21215 “MBT175356”, living culture ex-epitype CBS 102411. Romania,distr. Satu-Mare, Pir, on living leaves of G. ladanum, 27 Aug. 1973, G. Negrean s.n.,CBS H-18098.Notes: Jørstad (1965) reported comparable conidial size rangesin specimens on different host species, viz. G. speciosa (extremevalues 20–64 × 1–2.5 µm) and G. tetrahit (28–60 × 1–2 µm),although in most Norwegian collections on G. tetrahit, the maximumconidial length varied downwards to 48 µm. In the originaldiagnosis of S. galeopsidis conidia are described as 30–40 ×1–1.5 µm (Saccardo 1884), while Radulescu et al. (1973) reportedmeasurements ranging between 20–45 µm in length in collectionson various hosts. In the type material from BR investigated hereconidia are mostly 3–5-septate, 19–40 × 1.5–2 µm. In othermaterial available for the present study, maximum length of conidiawas only 44 µm in planta, whereas the strains obtained from it werecapable of forming conidia with a maximum length of 70 µm on OA.The differences with S. lamiicola are discussed under that species.Septoria galeopsidis is closely related to only some of the otherSeptoria species occurring on plants from the family Lamiaceae,especially S. melissae (CBS 109097) and S. stachydis. Septorialamiicola on Lamium spp., which is morphologically quite similarto S. galeopsidis, proves genetically very distinct, although thesetaxa can barely be distinguished by their ITS sequence (99.5 %).Several house-keeping genes do allow an easy identification ofthese species.Septoria heraclei (Lib.) Desm., Pl. crypt. Fr., Fasc. 11, no534. 1831. Fig. 21.Basionym: Ascochyta heraclei Lib., Pl. crypt. Ard., Cent. 1: no. 51.1830.≡ Cylindrosporium heraclei (Lib.) Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl. 115, I: 378. 1906 [non Oudem. 1873, nec Ellis & Everh. 1888].≡ Phloeospora heraclei (Lib.) Petr., Annls mycol. 17: 71. 1919 [non (Lib.)Maire, Bull. Soc. Mycol. France 46: 241. 1930].≡ Cylindrosporium umbelliferarum Wehm., Mycologia 39: 475. 1947.nom. nov.= Septoria heraclei-palmati Maire, Bull. Soc. Mycol. France 21: 167. 1905.Description in planta: Symptoms leaf spots numerous but small,irregular in outline, best visible on the upper side of the leaf,initially yellowish or ochreous, later becoming pale to dark brown,in places white due to loosening of the epidermis. Conidiomatapseudopycnidial, hypophyllous, one, rarely up to three in each260