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1 Botanische Staatssammlung München, Menzinger Strasse 67, D-80638
München, Germany
2 CBS Fungal Biodiversity Centre, P.O. Box 85167, 3508 AD Utrecht, The
Netherlands
3 Martin-Luther-Universität, Institut für Biologie, Geobotanik und
Botanischer Garten, Herbarium, Neuwerk 21, D-06099 Halle (Saale),
Germany
4 Plant & Environment Laboratory Biosecurity NZ, Ministry of Agriculture
& Forestry, P.O. Box 2095, Auckland 1140, New Zealand
5 Biotechnical Faculty, Department of Biology, Ve
na pot 111, SI-1000
Ljubljana, Slovenia
*
Correspondence: Konstanze Schubert,
konstanze.schubert{at}gmx.de
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Abstract |
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 TOP Abstract INTRODUCTIONMATERIAL AND METHODSRESULTSTaxonomyDISCUSSIONReferences |
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Taxonomic novelties: Cladosporium antarcticum K. Schub., Crous & U. Braun, sp. nov., C. herbaroides K. Schub., Zalar, Crous & U. Braun, sp. nov., C. ossifragi (Rostr.) U. Braun & K. Schub., comb. nov., C. pseudiridis K. Schub., C.F. Hill, Crous & U. Braun, sp. nov., C. ramotenellum K. Schub., Zalar, Crous & U. Braun, sp. nov., C. sinuosum K. Schub., C.F. Hill, Crous & U. Braun, sp. nov., C. subinflatum K. Schub., Zalar, Crous & U. Braun, sp. nov., C. subtilissimum K. Schub., Dugan, Crous & U. Braun, sp. nov., C. tenellum K. Schub., Zalar, Crous & U. Braun sp. nov., Davidiella macrocarpa Crous, K. Schub. & U. Braun, sp. nov., D. variabile Crous, K. Schub. & U. Braun, sp. nov.
Keywords Clonality / Davidiella / homothallism / new species / phylogeny / recombination / taxonomy
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INTRODUCTION |
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TOPAbstractINTRODUCTIONMATERIAL AND METHODSRESULTSTaxonomyDISCUSSIONReferences |
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Persoon (1794) introduced C. herbarum as Dematium herbarum Pers., which was later reclassified by Link (1809) as Acladium herbarum (Pers.) Link. In 1816, Link included C. herbarum together with three additional species in his newly described genus Cladosporium. Clements & Shear (1931) proposed C. herbarum as lectotype species of the latter genus, a decision followed by de Vries (1952) and Hughes (1958). Several authors provided detailed treatments of C. herbarum (de Vries 1952, Ellis 1971, Domsch et al. 1980, Prasil & de Hoog 1988), and there are literally thousands of records of this species in the literature. McKemy & Morgan-Jones (1991) and Ho et al. (1999) examined C. herbarum in culture and published detailed descriptions of its features in vitro.
Cladosporium macrocarpum Preuss, a second component within the herbarum complex, has hitherto been known and treated as an allied, but morphologically distinct species on the basis of its wider and somewhat larger, frequently 2-3-septate, more regularly verrucose conidia, shorter conidial chains and more pronounced prolongations of the conidiophores. Dugan & Roberts (1994) carried out examinations of morphological and reproductive aspects of both species, and in so doing demonstrated a morphological continuum between C. macrocarpum and C. herbarum, concluding that the name herbarum should have preference. Therefore, Ho et al. (1999) introduced the new combination C. herbarum var. macrocarpum (Preuss) M.H.M. Ho & Dugan. Although transitional forms have been discussed to occur between the two species, several authors still prefer to retain C. macrocarpum as a separate species.
In an attempt to elucidate the species within the C. herbarum
complex, therefore, a multilocus DNA sequence typing approach was used,
employing five genes, namely the internal transcribed spacers of the rDNA
genes (ITS), actin, calmodulin, translation elongation factor 1-
, and
histone H3. These data were supplemented with morphological examinations under
standardised conditions, using light and scanning electron microscopy, as well
as cultural characteristics and growth studies.
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MATERIAL AND METHODS |
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TOPAbstractINTRODUCTIONMATERIAL AND METHODSRESULTSTaxonomyDISCUSSIONReferences |
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Data analysis
The number of entities in the dataset of 79 strains was inferred with
STRUCTURE v. 2.2 software
(Pritchard et al.
2000, Falush et al.
2003) using an UPGMA tree of data of the ACT gene compared with
CAL, EF and HIS with the exclusion of the nearly invariant ITS region. For
this analysis group indications were derived from a tree produced with
MRAIC (Nylander
2004). The length of the burn-in period was set to 1 000 000,
number of MCMC repeats after burn-in 10 000, with admixture ancestry and
allele frequencies correlated models, assuming that all groups diverged from a
recent ancestral population and that allele frequencies are due to drift.
Uniform prior for ALPHA was set to 1.0 (default) and allele frequencies with
set to 1.0 (default). The numbers of MCMC repetitions after burn-in
were set as 10 000 and 100 000. The number of clusters (K) in
STRUCTURE was assumed from 5 to 7. Population differentiation
FST (index: 
) was calculated with 1-6 runs using the same
software. The null hypothesis for this analysis is no population
differentiation. When observed theta () is significantly different from
those of random data sets (p < 0.05), population differentiation is
considered.
Association of multilocus genotypes was screened with the multilocus option in BIONUMERICS v. 4.5. To test for reproductive mode in each population, the standardised index of association (I5A; Haubold et al. 1998) was calculated with START2 software (Jolley et al. 2001). The null hypothesis for this analysis is complete panmixia. The values of ISA were compared between observed and randomised datasets. The hypothesis would be rejected when p < 0.05. Mean genetic diversity (H) and diversities of individual loci were calculated with LIAN v. 3.5 (Haubold & Hudson 2000). Degrees of recombination or horizontal gene transfer were also visualised using SPLITS TREE v. 4.8 software (Huson & Bryant 2006). Split decomposition was carried out with default settings, i.e., character transformation using uncorrected (observed, "P") distances, splits transformation using "equal angle", and optimise boxes iteration set to 2.
Morphology
As the present study represents the first in a series dealing with
Cladosporium spp. and their Davidiella Crous & U. Braun
teleomorphs in culture, a specific, standardised protocol was established by
which all species complexes will be treated in future.
Morphology of the anamorph: Microscopic observations were made from colonies cultivated for 7 d under continuous near-ultraviolet light at 25 °C on SNA. Preparations were mounted in Shear's solution (Gams et al. 2007). To study conidial development and branching patterns, squares of transparent adhesive tape (Titan Ultra Clear Tape, Conglom Inc., Toronto, Canada) were placed on conidiophores growing in the zone between the colony margin and 2 cm inwards, and mounted between two drops of Shear's solution under a glass coverslip. Different types of conidia are formed by Cladosporium species for which different terms need to be adopted. Ramoconidia are conidia with usually more than one (mostly 2 or 3) conidial hilum, which typically accumulate at the tip of these conidia. Conidiogenous cells with more than one conidiogenous locus are first formed as apical parts of conidiophores. Such apical parts of conidiophores are called ramoconidia if they secede at a septum from the conidiophore (Kirk et al. 2001). The septum at which the ramoconidium secedes often appears to be somewhat refractive or darkened. Ramoconidia are characterised by having a truncate, undifferentiated base (thus they lack a differentiated, coronate basal hilum formed in the context of conidiogenesis) and they can be very long, aseptate to sometimes multi-septate. Although they were formed initially as part of the conidiophore, they function as propagules. Only few of the species known until now have the ability to form true ramoconidia. Secondary ramoconidia also have more than one distal conidial hilum but they always derive from a conidiogenous locus of an earlier formed cell, which can be either a conidiogenous cell or a ramoconidium. Secondary ramoconidia are often shorter but somewhat wider than ramoconidia; they are often septate, and typically have a narrowed base with a coronate hilum (Fig. 1). Conidia in Cladosporium are cells with a coronate basal hilum, which is formed in the context of conidiogenesis and with either a single (when formed as intercalary units in unbranched parts of chains) or without any distal conidial hilum (when formed at the tip of conidial chains). For the first, the term "intercalary conidium" and for the latter, "small terminal conidium" is used. Intercalary conidia typically are larger and more pigmented and have a more differentiated surface ornamentation than the small terminal conidia. In older literature true ramoconidia were often cited as "ramoconidia s. str.", whereas secondary ramoconidia have been referred to as "ramoconidia s. lat." Morphology of the teleomorph: Teleomorphs were induced by inoculating plates of 2 % tap water agar onto which autoclaved stem pieces of Urtica dioica (European stinging nettle) were placed. Inoculated plates were incubated on the laboratory bench for 7 d, after that period they were further incubated at 10 °C in the dark for 1-2 mo to stimulate teleomorph development. Wherever possible, 30 measurements (x 1 000 magnification) were made of conidia and ascospores, with the extremes of spore measurements given in parentheses. Cultural characteristics: Colonies were cultivated on PDA, MEA and OA plates for 14 d at 25 °C in the dark, after which the surface and reverse colours were rated using the charts of Rayner (1970). Linear growth was determined on MEA, PDA and OA plates by inoculating three plates per isolate for each medium, and incubating them for 14 d at 25 °C, after that period colony diameters were determined.
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RESULTS |
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TOPAbstractINTRODUCTIONMATERIAL AND METHODSRESULTSTaxonomyDISCUSSIONReferences |
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Forty equally most parsimonious trees (TL = 1 933 steps; CI = 0.569; RI = 0.786; RC = 0.447), one of which is shown in Fig. 3, were obtained from the parsimony analysis of the combined genes. Neighbour-joining analysis using three substitution models (uncorrected "p", Kimura 2-parameter and HKY85) on the sequence data yielded trees with identical topologies. These differed from the tree presented in Fig. 3 with regard to the placement of C. macrocarpum strain CPC 12054 which was placed as a sister branch to the C. bruhnei Linder clade in the distance analyses (results not shown) because it shares an identical CAL sequence. All cryptic species consisting of multiple strains are clustering in well-supported clades with bootstrap support values ranging from 71 % (C. herbarum) to 100 % [e.g. C. ramotenellum K. Schub., Zalar, Crous & U. Braun and C. ossifragi (Rostr.) U. Braun & K. Schub.]. The intraspecific variation in the C. bruhnei clade is due to genetic variation present in the sequence data of all loci except for ITS, those in the C. macrocarpum clade in all loci except for ITS and ACT, and those in the C. herbarum clade in all loci except for ITS and CAL (data not shown). However, none of the variation for these species could be linked to host specificity or morphological differences. In general, ITS data did not provide any resolution within the C. herbarum complex, whereas EF data provided species clades with very little intraspecific variation and ACT, CAL and HIS revealed increasing intraspecific variation (ACT the least and HIS the most).
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Taxonomy |
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TOPAbstractINTRODUCTIONMATERIAL AND METHODSRESULTSTaxonomyDISCUSSIONReferences |
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Key to the Davidiella species treated
Generic concept of the teleomorph
The introduction of the teleomorph genus Davidiella was mainly
based on phylogenetic studies within the Mycosphaerellaceae
(Braun et al. 2003),
where it could be demonstrated that "Mycosphaerella"
species with Cladosporium anamorphs formed a sister clade to
Mycosphaerella (Crous et al.
2000,
2001). Braun et al.
(2003) transferred five species
to Davidiella based on prior established anamorph-teleomorph
connections, though no details were provided pertaining to morphological
differences between Davidiella and Mycosphaerella. Aptroot
(2006) transferred several
additional species to Davidiella, and distinguished them from true
Mycosphaerella species by the presence of distinct, irregular
cellular inclusions (lumina) in their ascospores. Furthermore, Schoch et
al. (2006) placed
Davidiella in a separate family (Davidiellaceae) in the
Capnodiales. During the course of the present study, several fresh
specimens of Davidiella spp. were collected or induced in culture,
making it possible to circumscribe the genus as follows:
Davidiella Crous & U. Braun, Mycol. Progr. 2: 8. 2003, emend.
Ascomata pseudothecial, black to red-brown, globose, inconspicuous and immersed beneath stomata to superficial, situated on a reduced stroma, with 1(-3) short, periphysate ostiolar necks; periphysoids frequently growing down into cavity; wall consisting of 3-6 layers of textura angularis. Asci fasciculate, short-stalked or not, bitunicate, subsessile, obovoid to broadly ellipsoid or subcylindrical, straight to slightly curved, 8-spored. Pseudoparaphyses frequently present in mature ascomata, hyaline, septate, subcylindrical. Ascospores bi- to multiseriate, hyaline, obovoid to ellipsoid-fusiform, with irregular luminar inclusions, mostly thick-walled, straight to slightly curved; frequently becoming brown and verruculose in asci; at times covered in mucoid sheath. Cladosporium anamorph usually produced in culture, but not in all taxa.
Type species: Davidiella tassiana (De Not.) Crous & U. Braun, Mycol. Progr. 2: 8. 2003.
Description of Cladosporium species
Based on morphological examinations
(David 1997) and phylogenetic
studies employing DNA sequence data (Crous et al.
2000,
2001, 2007 - this volume,
Braun et al. 2003),
the generic concept of the genus Cladosporium has been stabilised.
Cladosporium is confined to Davidiella (Davidiellaceae,
Capnodiales) anamorphs with coronate conidiogenous loci and conidial hila
consisting of a central convex dome and a raised periclinal rim.
Cladosporium antarcticum K. Schub., Crous & U. Braun, sp. nov. MycoBank MB504573. Figs 6, 7 and 8.
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Differt a Cladosporio licheniphilo conidiophoris saepe non-ramosis, frequentibus geniculatis, angustioribus, (2-)3-4.5 µm, conidiis longioribus et angustioribus, 4-30 x 2.5-5 µm, 0-3-septatis, verruculosis vel verrucosis.
Mycelium immersed and superficial, dimorphic, branched, often with short lateral outgrowths, narrow hyphae 1-3 µm wide, hyaline to subhyaline, thin-walled, hyphae of the second type wider, 3.5-8(-9) µm, pluriseptate, often somewhat constricted at the septa, sometimes swollen, pale to dark greyish olivaceous or olivaceous-brown, smooth or verruculose, thick-walled, sometimes even two-layered (two distinct wall layers visible), 1(-1.5) µm thick, hyphae appearing consistently enveloped in polysaccharide-like material or covered by a slime coat. Conidiophores micronematous and macronematous, solitary or in loose groups, arising from plagiotropous or ascending hyphae, terminally or usually laterally. Macronematous conidiophores erect to somewhat decumbent, straight to somewhat flexuous or bent, cylindrical, once or several times slightly to distinctly geniculate towards the apex due to sympodial proliferation, unbranched or once branched, up to 120 µm long, 3-4.5 µm wide, sometimes slightly attenuated towards the apex, pluriseptate, up to eight septa, occasionally slightly constricted at the septa, pale to medium or even dark olivaceous-brown or greyish brown, paler towards apices, smooth to somewhat rough-walled, walls thickened but thinner-walled towards apices, sometimes slightly swollen at the base, up to 6 µm wide. Conidiogenous cells integrated, terminal and intercalary, once or several times slightly to distinctly geniculate, 10-33 µm long, proliferation sympodial, with several or numerous conidiogenous loci, at first terminal, later turning to one side of the stalk and situated on small lateral shoulders, up to 14 per cell, protuberant, denticulate, 1-1.5(-2) µm diam, thickened and darkened-refractive. Micronematous conidiophores as short lateral, peg-like outgrowths with a single apical scar or somewhat longer, occasionally once geniculate with several conidiogenous loci at the apex, 2-22 x 2-3 µm, pale greyish olivaceous, loci denticulate. Ramoconidia occasionally occurring, cylindrical, up to 30 µm long, 4-5 µm wide, 0-1-septate, concolorous with the tips of conidiophores, with a broadly truncate, unthickened and not darkened base, without dome and rim, 2.5 µm wide. Conidia catenate, in branched chains, straight, small terminal conidia obovoid, limoniform or narrowly ellipsoid, 4-14 x 2.5-4 µm [av. ± SD, 8.5 (± 3.3) x 3.5 (± 0.6)], 0(-1)-septate, secondary ramoconidia ellipsoid to cylindrical, often with several or numerous conidial hila crowded at the distal end, up to 12, 13-30 x 4-5 µm [av. ± SD, 20.1 (± 5.8) x 4.3 (± 0.5) µm], 0-3-septate, sometimes slightly constricted at the median septum, pale olivaceous-brown or greyish brown, minutely verruculose to verrucose (granulate under SEM), walls more or less thickened, rounded or slightly attenuated towards apex and base, hila protuberant, denticulate, 0.8-1.5(-2) µm diam, thickened and darkened-refractive; microcyclic conidiogenesis occurring.
Cultural characteristics: Colonies on PDA attaining 9 mm diam after 14 d at 25 °C, greenish olivaceous to grey-olivaceous, at the margin becoming dull green, reverse with a pale olivaceous-grey centre and a broad olivaceous-black margin, margin narrow, regular, entire edge, white, feathery, aerial mycelium sparse but colonies appearing felty, growth flat with somewhat elevated colony centre, prominent exudates not formed, sporulation dense, covering almost the whole colony. Colonies on MEA attaining 12 mm diam after 14 d at 25 °C, olivaceous-grey to iron-grey, iron-grey reverse, velvety to powdery, aerial mycelium sparse, sporulation profuse. Colonies on OA attaining 4 mm after 14 d at 25 °C, olivaceous-grey, aerial mycelium sparse, diffuse, growth flat, without prominent exudates, sporulating.
Specimen examined: Antarctica, King George, Arctowski, isolated from the lichen Caloplaca regalis (Teloschistaceae), C. Möller, No. 32/12, 1991, CBS-H 19857, holotype, isotype HAL 2024 F, culture ex-type CBS 690.92.
Substrate and distribution: On the lichen Caloplaca regalis; Antarctica.
Notes: This is the second genuine lichenicolous species of the genus Cladosporium. Cladosporium licheniphilum Heuchert & U. Braun, occurring on apothecia of Pertusaria alpina in Russia, is quite distinct from C. antarcticum by having subcylindrical or only slightly geniculate-sinuous, wider conidiophores, 5-8 µm, with numerous characteristic terminal branches and much shorter, 0-1-septate, smooth conidia, 3.5-13 x 3-7 µm (Heuchert & Braun 2006). Cladosporium lichenicola Linds. was invalidly published and C. arthoniae M.S. Christ. & D. Hawksw. as well as C. lichenum Keissl. are to be excluded from the genus Cladosporium since they do not possess the typical cladosporioid scar structure but inconspicuous, unthickened conidiogenous loci and conidial hila (Hawksworth 1979, Heuchert et al. 2005). The fungicolous species C. uredinicola Speg. and the foliicolous species C. alneum Pass. ex K. Schub. and C. psoraleae M.B. Ellis are morphologically superficially similar. However, C. uredinicola, a widespread fungus on rust fungi, downy mildews and powdery mildew fungi, differs in having somewhat longer and wider, smooth conidia, 3-39 x 2-6.5(-8) µm, and wider conidiogenous loci and conidial hila, 0.5-3 µm (Heuchert et al. 2005); C. alneum, which causes leaf spots on Alnus glutinosa, possesses longer and wider conidiophores, 25-260 x (2-)3-7(-8.5) µm, and somewhat shorter, smooth conidia (Schubert 2005, Schubert et al. 2006); and C. psoraleae, known from Myanmar on Psoralea corylifolia, can easily be distinguished from C. antarcticum by its smooth and wider conidia, 3.5-7 µm, and wider conidiogenous loci and conidial hila, 1-3 µm diam (Ellis 1972, Schubert 2005).
Cladosporium bruhnei Linder, Bull. Natl. Mus. Canada 97: 259. 1947. Figs 9, 10, 11 and 12.
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Hormodendrum hordei Bruhne, in W. Zopf, Beitr. Physiol.
Morph. nied. Org. 4: 1. 1894, non C. hordei Pass., 1887. Cladosporium herbarum (Pers.: Fr.) Link var. (
)
cerealium Sacc. f. hordei (Bruhne) Ferraris, Flora Ital.
Crypt., Pars I, Fungi, Fasc.13: 882. 1914. Cladosporium hordei (Bruhne) Pidopl., Gribnaja Flora
Grubych Kormov: 268. 1953, nom. illeg., homonym, non C.
hordei Pass., 1887.
Teleomorph: Davidiella allicina (Fr.: Fr.) Crous & Aptroot, in Aptroot, Mycosphaerella and its anamorphs: 2. Conspectus of Mycosphaerella. CBS Biodiversity Ser. 5: 30. 2006.
Basionym: Sphaeria allicina Fr., Kongl. Vetensk. Acad. Handl. 38: 247. 1817, sactioned by Fr., Syst. Mycol. 2: 437. 1823.
Sphaerella allicina (Fr.: Fr.) Auersw., in Gonn. &
Rabenh., Mycol. Europaea 5-6: 19. 1869. Ascomata pseudothecial, black, superficial, situated on a small stroma, globose, up to 250 µm diam; ostioles periphysate, with apical periphysoids present; wall consisting of 3-6 layers of reddish brown textura angularis. Asci fasciculate, bitunicate, subsessile, obovoid to broadly ellipsoid, straight to slightly curved, 8-spored, 65-90 x 16-25 µm; with pseudoparenchymatal cells of the hamathecium persistent. Ascospores tri- to multiseriate, overlapping, hyaline, with irregular lumina, thick-walled, straight to slightly curved, fusoid-ellipsoidal with obtuse basal end, and acutely rounded apical end, widest near the middle of the apical cell, medianly 1-septate, not to slightly constricted at the septum, (20-)25-27(-30) x (5.5-)6-7 µm.
Mycelium superficial, hyphae branched, 1.5-8 µm wide, pluriseptate, broader hyphae usually slightly constricted at the septa and somewhat swollen, hyaline to subhyaline, almost smooth to somewhat verruculose or irregularly rough-walled, sometimes appearing to have a slime coat, walls unthickened. Conidiophores macronematous, sometimes also micronematous, arising as lateral or terminal branches from plagiotropous or ascending hyphae, erect, straight to more or less flexuous, sometimes geniculate, nodulose, usually with small head-like swellings, sometimes also with intercalary nodules, sometimes swellings protruding and elongated to one side, unbranched, occasionally branched, (7-)20-330 µm, sometimes even longer, (2-)3-5 µm wide, swellings (4-)5-8 µm wide, pluriseptate, not constricted at the septa, septa sometimes not very conspicuous, subhyaline to pale brown or pale olivaceous, smooth or somewhat verruculose, walls unthickened or almost so, more thickened with age. Conidiogenous cells integrated, usually terminal, cylindrical with a terminal head-like swelling, sometimes with a second swelling, 15-40 µm long, proliferation sympodial, with few conidiogenous loci confined to swellings, up to five per swelling, loci protuberant, conspicuous, 1-2 µm diam, thickened and darkened-refractive. Conidia catenate, formed in branched chains, straight to slightly curved, small terminal conidia subglobose, ovoid to obovoid or somewhat limoniform, 4-9 x 2.5-3.5 µm [av. ± SD, 6.5 (± 1.5) x 3.1 (± 0.5) µm], aseptate; secondary ramoconidia and occasionally formed ramoconidia ellipsoid to subcylindrical or cylindrical, 10-24(-31) x 3-5(-7) µm [av. ± SD, 16.1 (± 4.1) x 4.1 (± 0.8) µm], rarely up to 40 µm long, 0-1(-3)-septate, very rarely 5-septate, subhyaline to pale brown or pale olivaceous, minutely verruculose to verrucose (mostly granulate with some muricate projections under SEM), walls unthickened or almost so, apex rounded or slightly attenuated towards apex and base, hila protuberant, conspicuous, 1-2 µm wide, up to 1 µm high, thickened and darkened-refractive; microcyclic conidiogenesis occurring.
Cultural characteristics: Colonies on PDA reaching 22-32 mm diam after 14 d at 25 °C, olivaceous-grey to iron-grey, sometimes whitish, smoke-grey to pale olivaceous due to abundant aerial mycelium covering almost the whole colony, with age collapsing becoming olivaceous-grey, occasionally zonate, velvety to floccose, margin narrow, entire edge, white, glabrous to somewhat feathery, aerial mycelium sparse to abundant, white, fluffy, growth regular, flat to low convex, sometimes forming few exudates in the colony centre, sporulating. Colonies on MEA reaching 21-32 mm diam after 14 d at 25 °C, grey-olivaceous, olivaceous-grey to dull green or iron-grey, sometimes whitish to pale smoke-grey due to abundant aerial mycelium, olivaceous-grey to iron-grey reverse, velvety, margin narrow, entire edge to slightly undulate, white, radially furrowed, glabrous to slightly feathery, aerial mycelium sparse to abundant, mainly in the centre, white, fluffy, growth convex to raised, radially furrowed, distinctly wrinkled in the colony centre, without prominent exudates, sporulating. Colonies on OA reaching 20-32 mm diam after 14 d at 25 °C, smoke-grey, grey-olivaceous to olivaceous-grey, greenish black or iron-grey reverse, margin narrow, entire edge, colourless to white, glabrous, aerial mycelium sparse to abundant, dark smoke-grey, diffuse, high, later collapsed, felty, growth flat, without prominent exudates, sporulation profuse.
Specimens examined: Sine loco et dato,
CBS 188.54 = ATCC
11290 = IMI 049638. Australia, N.S.W., Barrington Tops National Park,
isolated from leaves of Eucalyptus stellulata (Myrtaceae), 3 Jan.
2006, B. Summerell, CPC 12921. Belgium, isolated from Quercus robur
(Fagaceae), CBS
157.82; Kampenhout, isolated from Hordeum vulgare
(Poaceae), 26 June 2005, J.Z. Groenewald,
CBS-H 19856,
neotype designated here of C. bruhnei, isoneotype HAL 2023 F,
cultures ex-type CBS
121624 = CPC 12211, CPC 12212. Czech Republic, Lisen,
isolated from Polygonatum odoratum (Liliaceae),
CBS 813.71, albino
mutant of CBS
812.71. Germany,
CBS 134.31 = ATCC
11283 = IMI 049632; Nordrhein-Westfalen, Mühlheim an der Ruhr, isolated
from industrial water, IWW 727,
CBS 110024;
Sachsen-Anhalt, Halle (Saale), Robert-Franz-Ring, isolated from leaves of
Tilia cordata (Tiliaceae), 2004, K. Schubert, CPC 11386.
Netherlands, isolated from air,
CBS 521.68;
isolated from Hordeum vulgare, 1 Jan. 2005, P.W. Crous, CPC 12139;
isolated from man, skin, CBS
159.54 = ATCC 36948; Amsterdam, isolated from Thuja tincture,
CBS 177.71; Geleen,
St. Barbara Ziekenhuis, isolated from man, skin,
CBS 366.80,
CBS 399.80;
isolated from man, sputum, Aug. 1955,
CBS 161.55. New
Zealand, Otago, Lake Harris, isolated from Ourisia macrophylla
(Scrophulariaceae), 30 Jan. 2005, A. Blouin, Hill 1135, CPC 11840.
Russia, Moscow region, isolated from Polyporus radiatus
(Polyporaceae), Oct. 1978,
CBS 572.78 = VKM
F-405. Slovenia, Ljubljana, isolated from an air conditioning system,
2004, M. Butala, EXF-680 = CPC 12046; Seovlje, isolated from
hypersaline water from salterns (reserve pond), 2005, P. Zalar, EXF-389 = CPC
12042. Spain, Ebro Delta, isolated from hypersaline water from salterns
(crystallisation pond), 2004, P. Zalar, EXF-594 = CPC 12045. Sweden,
Skåne, on tip blight of living leaves of Allium sp.
(Alliaceae), Fr. no. F-09810, UPS-FRIES, holotype of
Davidiella allicina. U.S.A., New York, Geneva, isolated from
CCA-treated Douglas-fir pole,
CBS 115683 = ATCC
66670 = CPC 5101.
Substrate and distribution: Living and decaying plant material, man, air, hypersaline and industrial water; widespread.
Literature: Saccardo (1899: 1076), Linder (1947: 289).
Notes: Cladosporium bruhnei proved to be an additional component of the herbarum complex. The species resembles C. herbarum s. str. as already stated by Linder (1947), but possesses consistently narrower conidia, usually 2.5-5 µm wide, and the conidiophores often form only a single apical swelling. The species was described by Bruhne (l.c.) as Hormodendrum hordei from Germany but type material could not be located. Linder (1947) examined No. 1481a-5 (Canada, N. Quebec, Sugluk, on Elymus arenarius var. villosus, 31 Jul. 1936, E. Meyer), presumably in the National Museum, and stated that this specimen agreed well with the description and illustration given by Bruhne (l.c.). Although the species occurs on numerous substrates and is widely distributed, it has not yet been recognised as a distinct species since it has probably been interpreted as a narrow variant of C. herbarum.
Based on morphology and DNA sequence data, the CBS strain CBS 177.71 chosen by Prasil & de Hoog (1988) as representative living strain of C. herbarum, rather clusters together with isolates of C. bruhnei. The strain CBS 813.71 is an albino mutant of the latter species as it does not appear to contain colour pigment. Furthermore, all isolates from humans treated until now as C. herbarum proved to be conspecific with the narrow-spored C. bruhnei.
Although Davidiella tassiana (ascospores 17-25 x 6-8.5 µm, RO) was treated as synonymous to D. allicina (ascospores 20-27 x 6-7 µm, UPS) in Aptroot (2006), they differ in apical ascospore taper, with ascospores of D. allicina being acutely rounded, while those of D. tassiana are obtusely rounded. The same ascospore taper was also observed in the teleomorph of C. bruhnei, and thus the name D. allicina is herewith linked to C. bruhnei, which is distinct from C. herbarum, having D. tassiana as teleomorph.
Cladosporium herbaroides K. Schub., Zalar, Crous & U. Braun, sp. nov. MycoBank MB504574. Figs 13, 14 and 15.
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Differt a Cladosporio herbaro conidiis polymorphis, 3-33 x (2-)3-6(-7) µm, postremo latioribus, (3.5-)5-9(-11) µm, fuscis et crassitunicatis; et a Cladosporio macrocarpo conidiophoris leniter angustioribus, 3-5 µm latis, nodulis angustioribus, 5-8 µm latis.
Mycelium branched, (1-)2-8 µm wide, septate, often with small swellings and constrictions, subhyaline to pale brown or pale olivaceous-brown, smooth or almost so to somewhat verruculose, walls unthickened or almost so. Conidiophores macronematous and micronematous, arising lateral from plagiotropous hyphae or terminally from ascending hyphae. Macronematous conidiophores erect, straight to slightly flexuous, often geniculate, nodulose, with unilateral or multilateral swellings, often numerous swellings in short succession giving them a gnarled appearance, often forming somewhat protruding or prolonged lateral swellings or a branch-like prolongation below the terminal swelling (due to sympodial proliferation), unbranched or sometimes branched, 30-230 µm long or even longer, 3-5 µm wide, swellings 5-8 µm wide, septate, not constricted at septa, pale to medium olivaceous-brown, smooth or almost so, walls slightly thickened. Conidiogenous cells integrated, terminal or intercalary, cylindrical, usually nodulose to nodose forming distinct swellings, sometimes geniculate, 15-55 µm long, with numerous conidiogenous loci usually confined to swellings or situated on small lateral shoulders, sometimes on the top of short peg-like prolongations or denticles, loci protuberant, 1-2 µm diam, thickened and darkened-refractive. Micronematous conidiophores much shorter, narrower, paler, neither nodulose nor geniculate, arising laterally from plagiotropous hyphae, often only as short lateral denticles or branchlets of hyphae, erect, straight, conical to cylindrical, unbranched, 3-65 x 2-3 µm, mostly aseptate, sometimes up to five septa, subhyaline, smooth, walls unthickened. Conidiogenous cells integrated, terminal or conidiophores reduced to conidiogenous cells, conidiogenous loci solitary or sometimes as sympodial clusters of pronounced denticles, protuberant, 1-1.5 µm diam, thickened and somewhat darkened-refractive. Conidia polymorphous, two main morphological types recognisable, formed by the two different types of conidiophores, conidia formed by macronematous conidiophores catenate, in branched chains, straight to slightly curved, subglobose, obovoid, limoniform, ellipsoid to cylindrical, 3-33 x (2-)3-6(-7) µm [av. ± SD, 14.5 (± 7.9) x 5.2 (± 1.2) µm], 0-2(-3)-septate, sometimes slightly constricted at septa, septa median or somewhat in the lower half, pale to medium olivaceous-brown, verruculose to verrucose (granulate under SEM), walls slightly thickened, with up to three rarely four distal scars, with age becoming medium or even dark brown (chocolate brown), wider and more thick-walled, 5.5-33 x (3.5-)5-9(-11) µm [av. ± SD, 14.4 (± 6.9) x 7.2 (± 1.9) µm], walls up to 1 µm thick, hila protuberant, 0.8-2(-2.5) µm diam, thickened and darkened-refractive; microcyclic conidiogenesis occurring. Conidia formed by micronematous conidiophores paler and narrower, mostly formed in unbranched chains, sometimes in branched chains with up to three distal hila, straight to slightly curved, limoniform, narrowly fusiform, almost filiform to subcylindrical, 10-26(-35) x 2-3.5 µm [av. ± SD, 15.6 (± 6.2) x 2.9 (± 0.5) µm], 0-1(-3)-septate, subhyaline to pale brown, almost smooth to minutely verruculose, walls unthickened, hila protuberant, 1-1.5 µm diam, thickened and somewhat darkened-refractive.
Cultural characteristics: Colonies on PDA attaining 23 mm diam after 14 d at 25 °C, grey-olivaceous to olivaceous, olivaceous-grey reverse, velvety, margin regular, entire edge, narrow, feathery, aerial mycelium abundantly formed, loose, with age covering large parts of the colony, woolly, growth flat with somewhat elevated colony centre, folded, regular, deep into the agar, with few prominent exudates, sporulation profuse. Colonies on MEA attaining 24 mm diam after 14 d at 25 °C, grey- to greenish olivaceous, olivaceous-grey or iron-grey reverse, velvety to powdery, margin narrow, colourless, entire edge, somewhat feathery, aerial mycelium pale olivaceous-grey, sparse, growth convex, radially furrowed, folded in the colony centre, without prominent exudates, sporulating. Colonies on OA attaining 23 mm diam after 14 d at 25 °C, grey-olivaceous, margin more or less regular, entire edge, colourless, somewhat feathery, aerial mycelium whitish to smoke grey, at first sparse, later more abundantly formed, growth flat, without exudates, sporulation profuse.
Specimen examined: Israel, from hypersaline water of Eilat salterns, 2004, coll. N. Gunde-Cimerman, isol. M. Ota, CBS-H 19858, holotype, isotype HAL 2025 F, culture ex-type CBS 121626 = EXF-1733 = CPC 12052.
Substrate and distribution: Hypersaline water; Israel.
Notes: Cladosporium herbaroides is morphologically similar to C. herbarum but differs in having somewhat longer conidia becoming wider, darker and even more thick-walled with age [at first conidia 3-33 x (2-)3-6(-7) µm, with age (3.5-)5-9(-11) µm wide]. Besides that, the species often produces a second conidial type formed on micronematous conidiophores, giving rise to unbranched conidial chains which are almost filiform, limoniform, narrowly fusiform to subcylindrical, much narrower and paler than the ones formed by macronematous conidiophores, 10-26(-35) x 2-3.5 µm. In C. herbarum, conidia formed by micronematous conidiophores do not occur as frequently as in C. herbaroides, and differ in being often clavate and somewhat wider, up to 4(-5) µm wide. Cladosporium macrocarpum is easily distinguishable by having somewhat wider conidiophores (3-)4-6 µm, with distinctly wider swellings, 5-10 µm wide, and the conidia are usually (3-)5-9(-10) µm wide.
Cladosporium herbarum (Pers.: Fr.) Link, Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 7: 37. 1816: Fr., Syst. mycol. 3(2): 370. 1832. Figs 16, 17, 18 and 19.
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For additional synonyms see Dugan et al. (2004), Schubert (2005).
Teleomorph: Davidiella tassiana (De Not.) Crous & U. Braun, Mycol. Progr. 2: 8. 2003.
Basionym: Sphaerella tassiana De Not., Sferiacei Italici 1: 87. 1863.
Mycosphaerella tassiana (De Not.) Johanson, Öfvers.
Förh. Kongl. Svenska Vetensk.-Akad. 41: 167. 1884. Ascomata pseudothecial, black, globose, erumpent to superficial, up to 200 µm diam, with 1(-3) short, periphysate ostiolar necks; wall consisting of 3-6 layers of medium red-brown textura angularis. Asci fasciculate, bitunicate, subsessile, obovoid to broadly ellipsoid, straight to slightly curved, 8-spored, 65-85 x 13-17 µm. Pseudoparaphyses absent in host material, but remnants observed when studied in culture, hyaline, septate, subcylindrical, anastomosing, 3-4 µm wide. Ascospores tri- to multiseriate, overlapping, hyaline, with irregular luminar inclusions, thick-walled, straight to slightly curved, fusoid-ellipsoidal with obtuse ends, widest near middle of apical cell, medianly 1-septate, not to slightly constricted at the septum, tapering towards both ends, but more prominently towards the lower end, (17-)20-23(-25) x (6-)7(-8) µm; becoming brown and verruculose in asci. Ascospores germinating after 24 h on MEA from both ends, with spore body becoming prominently constricted at the septum, but not distorting, up to 7 µm wide, hyaline to pale brown and appearing somewhat verruculose, enclosed in a mucoid sheath, with germ tubes being irregular, somewhat nodular.
Mycelium superficial, loosely branched, (0.5-)1-5 µm wide, septate, sometimes constricted at septa, hyaline, subhyaline to pale brown, smooth or almost so to verruculose or irregularly rough-walled, sometimes appearing irregular in outline due to small swellings and constrictions, walls unthickened to somewhat thickened, cell lumen appearing to be granular. Conidiophores both macro- and micronematous, arising laterally from plagiotropous hyphae or terminally from ascending hyphae. Macronematous conidiophores
