Colletotrichum: complex species or species ... - CBS - KNAW

Damm et al.
Fig. 15. Colletotrichum kinghornii (from ex-holotype strain CBS 198.35). A–J. Conidiophores. K–L. Conidia. H–K. from Anthriscus stem. A–G, L. from SNA. A–L. DIC, Scale
bars: B = 10 µm. Scale bar of B applies to A–L.
Material examined: UK, Scotland, from Phormium tenax, unknown collection date,
N.L. Alcock (deposited in CBS collection Feb. 1935 by W.O. Kinghorn as Glomerella
phacidiomorpha), (CBS H-20909 holotype, culture ex-type CBS 198.35).
Notes: Kinghorn (1936) worked on two strains isolated from
Phormium from material collected in Scotland by N.L. Alcock. Both
of these were identified as C. phormii by Farr et al. (2006). One of
these is confirmed as C. phormii in this study, but we have found
the other (CBS 198.35) to be distinct in molecular terms. Kinghorn
named his material Glomerella phacidiomorpha, but Farr et al.
(2006) examined the type of that name and found it to be a species
of Phaeosphaeriopsis.
Colletotrichum kinghornii is one of the two species in the C.
acutatum complex with the largest conidia; only those of C. phormii
are bigger. However, strain CBS 198.35 hardly sporulates, and
the conidia measured were mostly formed in the aerial mycelium.
According to the molecular analyses, strain CBS 198.35 must be
considered separate at species rank from C. phormii, with several
sequence differences in almost every gene, and a single bp
difference in the ITS sequence (this was not detected in the Farr
et al. study). Colletotrichum kinghornii is most effectively separated
from other species using HIS3.
Closest match in blastn searches with the TUB2 sequence
of strain CBS 198.35 (with 98 % identity, 7 bp differences) was
Glomerella acutata isolate PCF 459 (EU635504) from strawberry
in Belgium (Debode et al. 2009) and with 98 % identity (8 bp
differences) isolate PT250 (= CBS 129953) AJ748624 from olive
in Portugal (see A6-1) (Talhinhas et al. 2005). This last strain
is assigned to C. rhombiforme in this study. With the GAPDH
sequence of strain CBS 198.35 there was no closer match from
GenBank than with 86 % identity.
Colletotrichum laticiphilum Damm, P.F. Cannon & Crous,
sp. nov. MycoBank MB800505. Fig. 16.
Etymology: latex = Greek for milk, latex and -philus = Greek for
loving; referring to the economically significant feature of the host
plant.
Sexual morph not observed. Asexual morph on SNA. Vegetative
hyphae 1–7.5 µm diam, hyaline, smooth-walled, septate,
branched. Chlamydospores not observed. Conidiomata not
developed, conidiophores formed directly on hyphae. Setae
not observed. Conidiophores hyaline, smooth-walled, simple or
septate and branched. Conidiogenous cells hyaline, smoothwalled,
ampulliform to conical, sometimes lacking a basal septum
and continuous with the conidiophore, discrete phialides measuring
6.5–15 × 3–4.5 µm, opening 1–1.5 µm diam, collarette 0.5–1.5 µm
long, periclinal thickening visible. Conidia hyaline, smooth-walled,
aseptate, straight, cylindrical with both ends ± acute or one end
round and one end slightly acute, (9.5–)13.5–19.5(–25.5) × (3–)
3.5–4(–4.5) µm, mean ± SD = 16.6 ± 3.1 × 3.8 ± 0.4 µm, L/W ratio
= 4.4, conidia of CBS 129827 smaller, measuring (5–)8–15(–18.5)
× (1.5–)2.5–4.5(–5.3) µm, mean ± SD = 11.5 ± 3.4 × 3.6 ± 0.9 µm,
L/W ratio = 3.2. Appressoria single, medium brown, smooth-walled,
subglobose, elliptical to clavate, the edge entire or rarely slightly
undulate, (5–)6.5–12(–16) × (4–)6–8(–8.5) µm, mean ± SD = 9.2
± 2.8 × 7.2 ± 1.0 µm, L/W ratio = 1.3, appressoria of CBS 129827
smaller, measuring (4–)5–7(–8) × (2.5–)3.5–5.5(–6) µm, mean ±
SD = 6.0 ± 1.1 × 4.5 ± 0.8 µm, L/W ratio = 1.3.
Asexual morph on Anthriscus stem. Conidiomata possibly
acervular, but no basal cells observed. Setae not observed.
Conidiophores hyaline to pale brown, smooth-walled, simple or
septate and branched, to 25 µm long. Conidiogenous cells hyaline
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