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

Verkley et al.Baarnsche bos, ex leaf spot of E. angustifolium, 17 Sep. 1967, L. Marvanová s.n.,living culture CBS 435.67 no longer available (infected with basidiomycete).Notes: In the type specimen of S. epilobii on Epilobium angustifolium(= Chamaenerion angustifolium), from BR, 1–3-septate conidia, 20–40 × 1–1.5 µm are observed. Although the collection of S. epilobiifrom Tirol was collected on another host species, E. fleischeri, itagrees morphologically well with the type material, and thereforethis Austrian collection is chosen here as epitype. It is consideredlikely that a single taxon is capable of infecting various membersof the genera Epilobium and its sister-genus Chamaenerion. Theconcept of S. epilobii maintained here concurs with that of mostauthors (Radulescu et al. 1973, Teterevnikova-Babayan 1987),except Vanev et al. (1997), who gave a much wider length range ofconidia, viz., 12–72 ×1–2 µm, but their concept of S. epilobii mayerroneously have been based in part on specimens of S. alpicola.Septoria epilobii is very distinct from S. alpicola Sacc. 1897, aspecies causing systemic infections in Epilobium spp. in alpineand boreal regions (type host E. alpinum), developing pycnidia onsymptomless leaves as well as stems that produce conidia, 24–95× 0.7–1.5(–2) µm, with up to 7 septa (Jørstad 1965).Septoria epilobii var. durieui Unamuno, which has beendescribed from E. duriaei in Spain, with conidia 30–55 × 1.5 µm, istentatively placed here in the synonymy of S. epilobi.As can be seen in the multilocus phylogeny (Fig. 2), the strainsof Septoria epilobii are closely related to CBS 102401, which wasisolated from Verbascum nigrum, and preliminarily identified as S.verbascicola Berk. & M.A. Curtis. This name is a nomen nudum andthe type should be studied. Other closely related species include S.taraxaci (CBS 567.75), S. stachydis, S. galeopsidis, and S. digitalis.Septoria erigerontis Peck, Rep. N.Y. St. Mus. nat. Hist. 24:87. 1872 [non Berk. & M.A. Curtis 1874; nec Hollós 1926,later homonyms]. Fig. 19.≡ Septoria erigerontea Sacc., Syll. Fung. 3: 547. 1884 [nom. illeg., Art. 52.superfluous nom. nov.].= Septoria erigeronata Thüm., Bull. Soc. Imp. Nat. Moscou 56: 132. 1881.= Septoria schnabliana (Allesch.) Died., KryptogFl. M. Brandenb. 9: 454. 1914.≡ Rhabdospora schnabliana Allesch., Hedwigia 34: 273. 1895.= Septoria chanousii Ferraris, Malpighia 16: 27. 1902.= Septoria stenactidis Vill, in Sydow, Annls mycol. 8: 493. 1910.?= Septoria bosniaca Picb., Glasnik Zemal. Muz. Bosn. Herceg. 45: 68. 1933.Description in planta: Symptoms leaf spots hologenous, scattered,circular to irregular, pale brown, indefinite or surrounded bya slightly darker margin. Conidiomata pycnidial, epiphyllous,numerous scattered in each leaf spot, subglobose to globose,brown to black, semi-immersed, 75–130 µm diam; ostiolumcentral, initially circular and 15–35 µm wide, later more irregular,up to 55 µm wide, surrounding cells dark brown and with morethickened walls; conidiomatal wall about 8–12.5 µm thick,composed of a homogenous tissue of hyaline, angular cells 2.5–4µm diam with relatively thin, hyaline walls, surrounded by a layer ofpale to dark brown cells, 2–5 µm diam, with somewhat thickenedwalls. Conidiogenous cells hyaline, discrete, rarely integrated in1–2-septate conidiophores, cylindrical to doliiform, or narrowly tobroadly ampulliform, holoblastic, proliferating mostly sympodially,rarely also percurrently with indistinct annellations, 6–10 ×2.5–4.5 µm. Conidia filiform, straight, slightly curved to flexuous,attenuated gradually to a narrowly rounded to pointed apex andnarrowly truncate base, (0–)1–3(–5)-septate, not constrictedaround the septa, hyaline, contents with several minute oil-dropletsand granular material in each cell in the living state, with minuteoil-droplets and granular contents in the rehydrated state, (17–)25–50(–62.5) × 1–1.5(–2) µm (rehydrated). Sexual morph unknown.Description in vitro: Colonies on OA 8–11 mm diam in 12 d (42–44mm in 7 wk), with an even, glabrous, colourless to pale red orcoral margin, the pigment also clearly diffusing beyond the margin;colonies spreading, the surface almost plane, immersed myceliumtranslucent and red everywhere (12 d), in the centre with denselyaggregated superficial pycnidial conidiomata often with distinctpapillate to rostrate openings, which later may elongate further,pycnidia elsewhere in radiating rows, later also in concentricrings, releasing milky white to pale buff droplets of conidial slime;aerial mycelium white, felty, scanty, mostly in the centre; reverseconcolorous. Colonies on CMA 7–10 mm diam in 12 d (50–59 mm in7 wk), as on OA, but immersed hyphae darker and olivaceous, butred pigmentation still distinct, especially around the colony margin.Colonies on MEA 4–7 mm diam in 12 d (45–48 mm in 7 wk), with aruffled, colourless to pale buff, plane marginal zone; colony initiallyrestricted, hemispherical after 12 d, with an irregularly pustulatewortysurface, later for the most plane and spreading, immersedmycelium very dark chestnut to black, aerial mycelium on elevatedsurface almost absent, but near margin forming short-tufty mat ofpure white hyphae; superficial pycnidial conidiomata releasing paleflesh or milky white droplets of conidial slime. Colonies on CHA6–8 mm diam in 12 d (29–36 mm in 7 wk), as on MEA, but in somesectors with an even, rosy-buff margin; colonies less elevated inthe centre than on MEA, covered with diffuse, woolly, greyish aerialmycelium in the centre, and a low, dense mat of reddish hyphaenear the margin; pycnidial conidiomata more numerous than onMEA, later in distinct, concentric patterns, producing flesh, latersalmon droplets of conidial slime.Conidiogenous cells (OA) as in planta, but more frequentlyproliferating percurrently and with distinct annellations. Conidia asin planta, up to 85 µm long and 2.5 µm wide.Hosts: Conyza spp. and Erigeron spp.Material examined: Austria, Tirol, Inntal W of Innsbruck, S of Telfs, along road 171,on living leaves of Erigeron annuus, 4 Aug. 2000, G. Verkley 1045, CBS H-21176,living culture CBS 109094, 109095; same substr., country unknown, M. Vurro, livingculture CBS 186.93 (sub S. schnabliana). South Korea, Namyangju, same substr.,H.D. Shin, 3 May 2006, living culture SMKC 21739 = KACC 42356 = CBS 128606;same country, loc. unknown, same substr., living culture CPC 12340 = CBS 131893.Notes: The material available for this study agreed generallywell with the detailed descriptions given for this species in recentliterature (Shin & Sameva 2004, Priest 2006). However, Priest(2006) did not observe sympodial proliferation in the conidiogenouscells. Shin & Sameva (2004) reported conidia up to 70 µm longin material from South Korea. Verkley & Starink-Willemse (2004)already showed that the ITS sequence of CBS 186.93 identifiedas S. schnabliana is identical to that in S. erigerontis (CBS109094), and suspected the conspecificity of this material. Strongevidence for this conspecificity is provided here, as the additionalgenes sequenced were all (almost) identical for the three isolatesinvestigated, and also for CBS 128606 (= KACC 42356) and CBS131893 (= CPC 12340) from the same host in South Korea.According to the diagnosis, Septoria stenactidis, describedfrom Stenactis annua (= E. annuum), has continuous (orindistinctly septate) conidia, 35–40 × 1 µm, which agrees well withS. erigerontis on the type host, and it was already placed in thesynonymy by Jørstad (1965), and recently also by Priest (2006).Priest also included S. chanousii in the synonymy of S. erigerontis.258