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

The Colletotrichum acutatum species complex
to iron grey, growth rate 19–21 mm in 7 d (29–32.5 mm in 10 d).
Conidia in mass whitish to pale salmon.
Material examined: Portugal, Mirandela, Torre de D. Chama, from anthracnose on
fruit of Olea europaea, Dec. 2003, P. Talhinhas (CBS H-20724 holotype, culture
ex-type CBS 129953 = PT250). USA, Washington, Long Beach, from Vaccinium
macrocarpon, 1993, Carris, culture CBS 131322 = DAOM 233523.
Notes: Talhinhas et al. (2005, 2009, 2011) found a diverse range of
C. acutatum isolates from olive fruit with anthracnose symptoms in
Portugal. One of these strains, PT250 (=CBS 129953) was found
to be significantly divergent from other groups within C. acutatum
based on ITS and beta-tubulin sequences, and was placed in the
new clade A6. Talhinhas’s olive strain here forms the type of C.
rhombiforme. A second strain that we identified as C. rhombiforme
and included here was isolated from Vaccinium macrocarpon
(American cranberry) in the USA, and was studied by Robideau
et al. (2008). Further representatives of this clade are likely to be
some of those isolated from Rhododendron in Sweden and Latvia
(strains S2, L3, L4, L5, L6) by Vinnere et al. (2002) that were
reported to belong to clade A6 by Sreenivasaprasad & Talhinhas
(2005) based on ITS sequencing. Since ITS does not distinguish
between all species, sequences of additional genes would be
necessary to confirm this placement.
A variety of Glomerella rufomaculans, Ga. rufomaculans var.
vaccinii Shear was described from leaves of Vaccinium macrocarpon
in New Jersey, USA with conidia and ascospores that agree in
size with C. rhombiforme. Its conidia were described as oblongcylindric,
subclavate, sometimes slightly curved (Shear 1907).
The variety was wrongly listed as Ga. fructigena var. vaccinii in
Sylloge Fungorum (Saccardo & Trotter 1913); MycoBank and Index
Fungorum list this taxon as separate species, Ga. rufomaculansvaccinii
Shear, MycoBank also as Ga. rufomaculansvaccinii
(orthographic variant) and additionally as Ga. fructigena var.
vaccinii. However a strain (CBS 124.22) deposited 1922 in the CBS
collection by L.C. Shear as Ga. rufomaculans var. vaccinii is lacking
host information and belongs to the C. gloeosporioides complex
(Weir et al. 2012, this issue).
Colletotrichum rhombiforme is closely related to C. acerbum, C.
australe, C. kinghornii and C. phormii, which together form a sister
clade to C. salicis. In this study, only strains of C. rhombiforme and
C. salicis formed sexual morphs in culture. The ascospores of the
two species have the same size, but differ in shape. Additionally,
conidia of C. salicis formed on SNA are smaller than those of C.
rhombiforme, and conidia of C. rhombiforme formed on Anthriscus
stem are sometimes ellipsoidal or limoniform while those of C.
salicis are uniformly cylindrical.
Colletotrichum rhombiforme is separated from other species by
all sequences studied except the CHS-1 sequence, which is the
same as that of C. acerbum. It can best be identified with TUB2
and ITS. The closest match in a blastn search with the TUB2
sequence of CBS 129953 with 100 % identity was AJ748624,
the sequence generated from the same isolate by Talhinhas et
al. (2005), all other isolates showed ≤ 97 % sequence identity.
With the GAPDH sequence there was no closer match than 88
% identity. Closest matches with the ITS sequence (with 100 %
identity) were AJ749700 from isolate PT250 (= CBS 129953)
(Talhinhas et al. 2005), AF411704, AF411706, AF411707 and
AF411719 from Rhododendron isolates L3, L5, L6, S2 from Latvia
and Sweden (Vinnere et al. 2002) and with 99 % identity (1 bp
difference) AF411705 from Rhododendron isolate L4 (Vinnere et
al. 2002) and EF672241 from Vaccinium isolate DAOM 233253 (=
CBS 131322, the other isolate of C. rhombiforme included in this
study) (Robideau et al. 2008).
Colletotrichum salicis (Fuckel) Damm, P.F. Cannon &
Crous, comb. nov. MycoBank MB800518. Fig. 27.
Basionym: Sphaeria salicis Fuckel, Jahrb. nass. Ver. Naturk. 23–
24: 115. 1870.
≡ Sphaeria salicis Auersw., in Fuckel, Fungi Rhen. no. 913, in sched.
1864, nom. nud.
≡ Physalospora salicis (Fuckel) Sacc., Syll. fung. (Abellini) 1: 439. 1882.
≡ Physosporella salicis (Fuckel) Höhn., Annls mycol. 16: 58. 1918.
≡ Anisostomula salicis (Fuckel) Petr., Hedwigia 65: 198. 1925.
≡ Plectosphaera salicis (Fuckel) Arx & E. Müll., Beitr. Kryptfl. Schweiz 11
(no. 1): 204. 1954.
≡ Glomerella salicis (Fuckel) L. Holm, in Holm & Ryman, Thunbergia 30:
6. 2000.
= Phyllachora amenti Rostr., Skr. Christiana Vidensk.-Selsk. Forhandl. 9: 5.
1891.
≡ Haplothecium amenti (Rostr.) Theiss. & Syd., Annls Mycol. 13: 615.
1915.
≡ Glomerella amenti (Rostr.) Arx & E. Müll., Beitr. Kryptfl. Schweiz 11 (no.
1): 197. 1954.
= Glomerella lycopersici F. Krüger, Arbeiten Kaiserl. Biol. Anst. Land- Forstw.
9: 308. 1913.
≡ Gloeosporium lycopersici F. Krüger, Arbeiten Kaiserl. Biol. Anst. Land-
Forstw. 9: 308. 1913.
≡ Colletotrichum kruegerianum Vassiljevsky, Fungi Imperfecti Parasitici 2:
321. 1950 [non C. lycopersici Chester 1891].
= Physalospora miyabeana Fukushi, Annls phytopath. Soc. Japan 1 (no. 4):
7. 1921.
≡ Glomerella miyabeana (Fukushi) Arx, Phytopath. Z. 29: 448. 1957.
Sexual morph developed on Anthriscus stem. Ascomata globose
to pyriform, ostiolate, medium brown, darker towards the ostiole,
150–200 × 185–250 µm. Peridium 10–15 µm thick, composed
of pale to medium brown flattened angular cells 5–15 µm diam.
Ascogenous hyphae hyaline, smooth-walled, delicate. Interascal
tissue composed of paraphyses, hyaline, septate, 30–80 × 2–3.5
µm, widest part at the base, tips round. Asci cylindrical, 55–88
× 8–12 µm, 8-spored. Ascospores arranged uni- to biseriately,
aseptate, hyaline, smooth-walled, ovoid, fusiform, cigar-shaped
or cylindrical, one end acute and one end obtuse or both ends
obtuse, sometimes very slightly curved, (12.5–)13–15(–17) ×
(4.5–)5–6(–6.5) µm, mean ± SD = 14.1 ± 1.1 × 5.4 ± 0.5 µm,
L/W ratio = 2.6.
Asexual morph on SNA. Vegetative hyphae 1–8 µm diam,
hyaline to pale brown, smooth-walled, septate, branched.
Chlamydospores not observed. Conidiomata absent,
conidiophores formed directly on hyphae. Setae not observed.
Conidiophores hyaline, smooth-walled, simple or septate
and branched. Conidiogenous cells hyaline, smooth-walled,
cylindrical to elongate ampulliform, sometimes intercalary (necks
not separated from hyphae by a septum), 5–20 × 2–3.5 µm,
opening 1–1.5 µm diam, collarette 0.5–1 µm long, periclinal
thickening visible. Conidia hyaline, smooth-walled, aseptate,
straight, cylindrical to clavate with one end round and one end ±
acute to truncate, (8.5–)10.5–15.5(–19.5) × (3.5–)3–4.5(–5) µm,
mean ± SD = 13.0 ± 2.4 × 4.0 ± 0.5 µm, L/W ratio = 3.2, conidia
of strains CBS 115.14 and CBS 465.83 narrower, measuring (9–)
10.5–15(–17) × 2.5–3.5(–4) µm, mean ± SD = 12.7 ± 2.3 × 3.1
± 0.5 µm, L/W ratio = 4.1 and (7.5–)9.5–15.5(–22) × 3–3.5(–4.5)
µm, mean ± SD = 12.4 ± 3.1 × 3.3 ± 0.4 µm, L/W ratio = 3.8.
Appressoria single or in small groups, medium brown, outline
mostly clavate, elliptical or ovate, the edge entire or undulate,
rarely lobate, (6–)8–15(–19.5) × (5–)6.5–8.5(–9.5) µm, mean ±
SD = 11.5 ± 3.5 × 7.6 ± 1.0 µm, L/W ratio = 1.5.
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