Highlights of the Didymellaceae - Studies in Mycology
Highlights of the Didymellaceae - Studies in Mycology
Highlights of the Didymellaceae - Studies in Mycology
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(65–)95–200(–220) μm with a s<strong>in</strong>gle, conspicuous, non-papillate<br />
ostiole. Pycnidial wall pale brown, pseudoparenchymatous,<br />
composed <strong>of</strong> isodiametric cells, 3–5 layers, (6–)8.5–14.5(–16) μm<br />
thick, outer 1–2 layers slightly pigmented. Conidiogenous cells<br />
phialidic, hyal<strong>in</strong>e, simple, smooth, doliiform to ampulliform, variable<br />
<strong>in</strong> size, ca. (3–)3.5–5 × 3–4(–5) μm. Conidia variable <strong>in</strong> shape and<br />
size, subglobose to oval or obtuse, th<strong>in</strong>-walled, smooth, aseptate,<br />
measur<strong>in</strong>g (5–)5.5–7.5(–8.5) × 3–4.5(–5) μm, with 0–2(–3) m<strong>in</strong>ute<br />
guttules, <strong>in</strong>itially hyal<strong>in</strong>e, but brown at maturity. Conidial exudates<br />
not recorded.<br />
Culture characteristics: Colonies on OA 55–68 mm diam after 7 d,<br />
marg<strong>in</strong> regular. Aerial mycelium white, floccose to woolly. Immersed<br />
mycelium greenish olivaceous to olivaceous near <strong>the</strong> colony centre.<br />
Abundant black pycnidia are scattered over <strong>the</strong> medium; reverse<br />
concolourous. Colonies on MEA 65–75 mm diam after 7 d, marg<strong>in</strong><br />
regular. Aerial mycelium cover<strong>in</strong>g <strong>the</strong> whole colony, compact, white<br />
to pale grey, with olivaceous t<strong>in</strong>ges near <strong>the</strong> colony centre; reverse<br />
olivaceous-black.<br />
Specimen exam<strong>in</strong>ed: Ukra<strong>in</strong>e, Crimea, <strong>in</strong> <strong>the</strong> vic<strong>in</strong>ity <strong>of</strong> Feodosiya, on Microsphaera<br />
alphitoides from Quercus sp., 1979, O.L. Rudakov, CBS H-20276, culture CBS<br />
633.92 = ATCC 36786, VKM MF-325.<br />
Notes: The epi<strong>the</strong>t used for <strong>the</strong> description <strong>of</strong> this species <strong>in</strong> <strong>the</strong><br />
genera Cic<strong>in</strong>obolus and Ampelomyces could not be transferred to<br />
<strong>the</strong> genus Phoma as Ph. querc<strong>in</strong>a is already occupied. This name,<br />
however, refers to a Phyllosticta species (Van der Aa & Vanev<br />
2002). Therefore, a new name is proposed here for <strong>the</strong> present<br />
species.<br />
Kiss & Nakasone (1998) already found that several fastgrow<strong>in</strong>g<br />
Ampelomyces species were phylogenetically dist<strong>in</strong>ct from<br />
<strong>the</strong> type species, which is characterised by a ra<strong>the</strong>r slow growth<br />
rate, and suggested that A. querc<strong>in</strong>us belonged to Phoma. This<br />
f<strong>in</strong>d<strong>in</strong>g was supported by results obta<strong>in</strong>ed <strong>in</strong> later studies (Sullivan<br />
& White 2000, Szentiványi et al. 2005).<br />
Phoma gossypiicola Gruyter, Persoonia 18(1): 96. 2002.<br />
Specimen exam<strong>in</strong>ed: U.S.A., Texas, from a leaf <strong>of</strong> Gossypium sp., 1963, L.S. Bird<br />
CBS H-9006, culture CBS 377.67.<br />
Phoma <strong>in</strong>fossa Ellis & Everh., J. Mycol. 4(10): 102. 1888,<br />
emend. Aveskamp et al., Mycologia 101. 373. 2009.<br />
Specimens exam<strong>in</strong>ed: Argent<strong>in</strong>a, Buenos Aires Prov<strong>in</strong>ce, La Plata, from leafs<br />
<strong>of</strong> Frax<strong>in</strong>us pennsylvanica, 2008, M. Murace, neotype CBS H-20145, culture exneotype<br />
CBS 123395; Buenos Aires Prov<strong>in</strong>ce, La Plata, from leafs <strong>of</strong> Frax<strong>in</strong>us<br />
pennsylvanica, 2008, M. Murace, CBS 123394.<br />
Group G:<br />
This group (BPP = 1.00, RBS = 99 %) consists <strong>of</strong> Ph. subherbarum<br />
and Ph. pedeiae sp. nov. Although <strong>the</strong> first species name suggests<br />
a close resemblance with <strong>the</strong> type species Ph. herbarum, it is<br />
phylogenetically dist<strong>in</strong>ct. Both Ph. herbarum and Ph. subherbarum<br />
are accommodated <strong>in</strong> section Phoma, but are dist<strong>in</strong>ct <strong>in</strong> colony<br />
characters: <strong>in</strong> contrast to Ph. herbarum, Ph. subherbarum does not<br />
react to <strong>the</strong> application <strong>of</strong> a droplet <strong>of</strong> NAOH (De Gruyter et al.<br />
1993). The growth rate <strong>of</strong> Ph. subherbarum is also considerably<br />
faster, as a colony can cover <strong>the</strong> plate surface with<strong>in</strong> 1 wk.<br />
Boerema et al. (2004) hypo<strong>the</strong>sised that Ph. subherbarum is<br />
from American orig<strong>in</strong>. In contrast, both stra<strong>in</strong>s <strong>of</strong> Ph. pedeiae were<br />
found <strong>in</strong> <strong>the</strong> Ne<strong>the</strong>rlands. Both species <strong>in</strong> this clade appear to have a<br />
plurivorous nature. The novel species Ph. pedeiae is described below.<br />
www.studies<strong>in</strong>mycology.org<br />
Phoma And relAted pleoSporAleAn generA<br />
Phoma pedeiae Aveskamp, Gruyter & Verkley, sp. nov.<br />
MycoBank MB515594. Fig. 4.<br />
Conidia ellipsoidea vel cyl<strong>in</strong>drica, glabra, hyal<strong>in</strong>a, cont<strong>in</strong>ua, 3–4.5 × 1.5–2.5 μm,<br />
0–2(–3) guttulis praedita. Matrix conidiorum cremeo-alba.<br />
Etymology: Named after <strong>the</strong> <strong>in</strong>stitute that has facilitated most <strong>of</strong><br />
<strong>the</strong> research on <strong>the</strong> taxonomy <strong>of</strong> <strong>the</strong> genus Phoma and affiliated<br />
genera <strong>in</strong> <strong>the</strong> past decade, <strong>the</strong> PD (Plantenziektenkundige Dienst –<br />
Dutch Plant Protection Service). Both isolates <strong>of</strong> this species were<br />
collected and preserved by employees <strong>of</strong> this <strong>in</strong>stitute.<br />
Pycnidia solitary or confluent, produced on <strong>the</strong> agar surface,<br />
globose to ellipsoidal, glabrous, (90–)100–230(–255) × (75–)<br />
90–155(–165) μm with 1–2 conspicuous, non-papillate ostioles.<br />
Pycnidial wall pseudoparenchymatous, composed <strong>of</strong> oblong to<br />
isodiametric cells, 3–5 layers, 11–17 μm thick. Conidiogenous cells<br />
phialidic, hyal<strong>in</strong>e, simple, smooth, flask-shaped, relatively small,<br />
ca. 3.5–4(–4.5) × 3–4 μm. Conidia ellipsoidal to cyl<strong>in</strong>drical, th<strong>in</strong>walled,<br />
smooth, hyal<strong>in</strong>e, aseptate 3–4.5 × 1.5–2.5 μm, with 0–2(–3)<br />
guttules. Conidial matrix creme-white.<br />
Culture characteristics: Colonies on OA, 65–75 mm diam after 7 d,<br />
marg<strong>in</strong> regular. Immersed mycelium olivaceous. Aerial mycelium<br />
floccose, white or smoke-grey to greenish olivaceous. Abundant<br />
black pycnidia are scattered over <strong>the</strong> medium; reverse concolourous<br />
with some reddish t<strong>in</strong>ges. Colonies on MEA 55–65 mm diam after<br />
7 d, marg<strong>in</strong> regular. Aerial mycelium cover<strong>in</strong>g <strong>the</strong> whole colony,<br />
floccose, smoke-grey to greenish olivaceous, white near <strong>the</strong> centre<br />
<strong>of</strong> <strong>the</strong> colony; reverse olivaceous-black or bay. Agar colour changes<br />
to bay due to diffusible pigments produced by <strong>the</strong> fungus. Colonies<br />
on CHA similar as on MEA, but somewhat faster grow<strong>in</strong>g, 70–80 mm<br />
diam after 7 d. Application <strong>of</strong> NaOH did not have any effect.<br />
Specimens exam<strong>in</strong>ed: The Ne<strong>the</strong>rlands, Aalsmeer region, on Schefflera<br />
elegantissima, 1992, J. de Gruyter, holotype designated here CBS H-20239,<br />
culture ex-holotype CBS 124517 = PD 92/612A; on Orchidaceae sp., 1984, J. de<br />
Gruyter, CBS 124516 = PD 84/453.<br />
Notes: Phoma pedeiae has been found <strong>in</strong> association with several<br />
tropical ornamental pot plants <strong>in</strong> Dutch greenhouses. Only mild<br />
disease symptoms were recorded from this species, and <strong>the</strong>refore<br />
<strong>the</strong> fungus was not fur<strong>the</strong>r studied. Phylogenetically, this species<br />
is found <strong>in</strong> close relation to Ph. subherbarum (BPP= 1.00; RBS =<br />
99 %), which is probably a weak pathogen and saprobe <strong>of</strong> different<br />
plant substrates occurr<strong>in</strong>g on <strong>the</strong> American cont<strong>in</strong>ent (De Gruyter<br />
et al. 1993).<br />
Phoma subherbarum Gruyter, Noordel. & Boerema,<br />
Persoonia 15(3): 387. 1993.<br />
Specimens exam<strong>in</strong>ed: Canada, from Zea mays, holotype L 992.177.439, culture<br />
ex-holotype CBS 250.9292 = DAOM 171914 = PD 92/371; from Zea mays, May<br />
1978, G.A. Neish, CBS 305.79A = DAOM 170848; Peru, from Solanum sp., CBS<br />
249.92 = PD 78/1088.<br />
Group H:<br />
Phoma bellidis and Ph. senecionis are found <strong>in</strong> association with two<br />
plant genera from <strong>the</strong> Compositae family: Bellis spp. and Senecio<br />
spp. respectively (De Gruyter et al. 1993). The distantly related<br />
Ph. digitalis is a pathogen <strong>of</strong> Digitalis spp. (Scrophulariaceae), but<br />
shares <strong>the</strong> feature with Ph. bellidis that it is also recorded as a<br />
seed-pathogen (Boerema & Dorenbosch 1979). In contrast, Ph.<br />
senecionis is only known as a necrophyte.<br />
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