Harknessia
Cooke, Grevillea 9: 85. 1881. Fig. 18.
Fig. 18. Harknessia spp. A–E. Disease symptoms on Eucalyptus. A. Harknessia fusiformis (CPC 13649). B. Harknessia hawaiiensis (CPC 15003). C. Harknessia ravenstreetina (ex-type CBS 132125). D. Harknessia rhabdosphaera (CPC 13593). E. Harknessia globispora (CPC 14924). F–L. Sexual morph of Harknessia eucalyptorum (CPC 12697). F. Ascoma with short neck, oozing ascospores. G, H. Paraphyses and asci. I, J. Asci. K. Paraphyses and ascal tip. L. Ascospores. M–AA. Asexual morphs. M. Sporulating colony on OA of Harknessia ellipsoidea (ex-type CBS 132121). N–R. Conidiogenous cells giving rise to conidia. N, O. Harknessia gibbosa (ex-type CBS 120033). P. Harknessia pseudohawaiiensis (CPC 17380). Q. Harknessia ravenstreetina (ex-type CBS 132125). R. Harknessia renispora (CPC 17163). S–X. Conidia. S, T. Harknessia australiensis (ex-type CBS 132119). U. Harknessia kleinzeeina (ex-type CPC 16277). V. Harknessia eucalyptorum (CPC 12697). W. Harknessia ravenstreetina (ex-type CBS 132125). X. Harknessia renispora (CPC 17163). Y. Microconidiogenous cells giving rise to microconidia of Harknessia renispora (CPC 17163). Z, AA. Microconidia. Z. Harknessia renispora (CPC 17163). AA. Harknessia pseudohawaiiensis (CPC 17380). Scale bars = 10 μm. Pictures taken from Crous et al. (2012c).
Synonyms: Caudosporella Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1 123: 135. 1914.
Mastigonetron Kleb., Mykol. Zentbl. 4: 17. 1914.
Cymbothyrium Petr., Sydowia 1: 148. 1947.
Classification: Sordariomycetes, Sordariomycetidae, Diaporthales, Harknessiaceae.
Type species: Harknessia eucalypti Cooke. Representative strain: CBS 342.97.
DNA barcode (genus): LSU.
DNA barcodes (species): ITS, cal, tub2. Table 7. Fig. 19.
Table 7. DNA barcodes of accepted Harknessia spp.
| Species | Isolates1 | GenBank accession number2 | References | ||
|---|---|---|---|---|---|
| ITS | cal | tub2 | |||
| Harknessia arctostaphyli | CBS 137228ET | KJ152781 | – | KJ179923 | Moreno-Rico et al. (2014) |
| Ha. australiensis | CBS 132119T | JQ706085 | JQ706171 | JQ706130 | Crous et al. (2012c) |
| Ha. banksiae | CBS 142539T | KY979782 | KY979872 | KY979938 | Crous et al. (2017a) |
| Ha. banksiae-repens | CBS 142541T | KY979785 | KY979875 | KY979940 | Crous et al. (2017a) |
| Ha. banksiigena | CBS 142540T | KY979784 | KY979874 | – | Crous et al. (2017a) |
| Ha. bourbonica | CBS 143913T | MG934433 | MG934512 | – | Present study |
| Ha. capensis | CBS 111829T | AY720719 | AY720782 | AY720751 | Lee et al. (2004) |
| Ha. communis | CBS 142538T | KY979778 | KY979868 | – | Crous et al. (2017a) |
| Ha. corymbiae | CPC 33289T | MG934434 | MG934513 | MG934507 | Present study |
| Ha. cupressi | CBS 143914T | MG934435 | MG934514 | – | Present study |
| CPC 30174 | MG934436 | MG934515 | – | Present study | |
| Ha. ellipsoidea | CBS 132121T | JQ706087 | JQ706173 | JQ706132 | Crous et al. (2012c) |
| Ha. eucalypti | CBS 342.97 | AY720745 | AY720808 | AY720777 | Lee et al. (2004) |
| Ha. eucalyptorum | CBS 111115T | AY720747 | AY720810 | AY720779 | Lee et al. (2004) |
| Ha. fusiformis | CBS 110785T | AY720721 | AY720784 | AY720753 | Lee et al. (2004) |
| Ha. gibbosa | CBS 120033T | EF110615 | JQ706182 | JQ706142 | Crous et al., 2007, Crous et al., 2012c |
| Ha. globispora | CBS 111578T | AY720722 | AY720785 | AY720754 | Lee et al. (2004) |
| Ha. hawaiiensis | CBS 114811 | AY720723 | AY720786 | AY720755 | Lee et al. (2004) |
| Ha. ipereniae | CBS 120030T | EF110614 | JQ706192 | JQ706151 | Crous et al., 2007, Crous et al., 2012c |
| Ha. karwarrae | CBS 115648 | AY720748 | AY720811 | AY720780 | Lee et al. (2004) |
| Ha. kleinzeeina | CPC 16277T | JQ706108 | JQ706193 | JQ706152 | Crous et al. (2012c) |
| Ha. leucospermi | CBS 775.97T | AY720727 | AY720790 | AY720759 | Lee et al. (2004) |
| Ha. malayensis | CBS 142544T | KY979789 | KY979879 | KY979941 | Crous et al. (2017a) |
| Ha. molokaiensis | CBS 114877T | AY720749 | AY720812 | AY579335 | Lee et al., 2004, Mostert et al., 2005 |
| Ha. pellitae | CBS 142543T | KY979788 | KY979878 | – | Crous et al. (2017a) |
| Ha. pilularis | CPC 33218T | MG934438 | MG934517 | MG934508 | Present study |
| CPC 33356 | MG934439 | MG934518 | MG934509 | Present study | |
| Ha. platyphyllae | CBS 142542T | KY979787 | KY979877 | – | Crous et al. (2017a) |
| Ha. proteae | CBS 136426T | KF777162 | – | – | Crous et al. (2013) |
| Ha. protearum | CBS 112618T | AY720732 | AY720795 | AY720764 | Lee et al. (2004) |
| Ha. pseudohawaiiensis | CBS 132124T | JQ706111 | JQ706196 | JQ706155 | Crous et al. (2012c) |
| Ha. ravenstreetina | CBS 132125T | JQ706112 | JQ706197 | JQ706156 | Crous et al. (2012c) |
| Ha. renispora | CBS 153.71IsoT | AY720737 | AY720800 | AY720769 | Lee et al. (2004) |
| Ha. rhabdosphaera | CBS 122373 | JQ706118 | JQ706201 | JQ706161 | Crous et al. (2012c) |
| Ha. spermatoidea | CBS 132127ET | JQ706120 | JQ706203 | JQ706163 | Crous et al. (2012c) |
| Ha. syzygii | CBS 111124T | AY720738 | AY720801 | AY720770 | Lee et al. (2004) |
| Ha. uromycoides | CBS 110729 | AY720739 | AY720802 | AY720771 | Lee et al. (2004) |
| Ha. viterboensis | CBS 115647T | AY720740 | AY720803 | AY720772 | Lee et al. (2004) |
| Ha. weresubiae | CBS 132128ET | JQ706122 | JQ706205 | JQ706165 | Crous et al. (2012c) |
- 1
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CBS: Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands; CPC: Culture collection of Pedro Crous, housed at the Westerdijk Fungal Biodiversity Institute. T, ET and IsoT indicate ex-type, ex-epitype and ex-isotype strains, respectively.
- 2
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ITS: internal transcribed spacers and intervening 5.8S nrDNA; cal: partial calmodulin gene; tub2: partial β-tubulin gene.
Fig. 19. RAxML phylogram obtained from the combined ITS (643 bp), cal (499 bp) and tub2 (838 bp) sequence alignment of all accepted species of Harknessia. The tree was rooted to Cryphonectria parasitica. The novelties proposed in this study are indicated in bold. RAxML bootstrap support (BS) values above 70 % and Bayesian posterior probability scores above 0.95 are shown at the nodes. GenBank accession numbers were listed in Table 7 or in Crous et al. (2012c). T, ET and IsoT indicate ex-type, ex-epitype and ex-isotype strains, respectively. TreeBASE: S21899.
Ascomata perithecial, single or aggregated, immersed, brown; necks emergent to depressed; ascomatal wall of 3–5 layers of brown cells of textura angularis. Paraphyses hyaline, septate, dispersed between asci. Asci 8-spored, unitunicate, cylindrical to clavate, short pedicellate, with J- apical ring. Ascospores uni- to biseriate, ellipsoid to fusoid, hyaline, aseptate, thick-walled, guttulate, smooth-walled. Conidiomata erumpent, scattered, pycnidial, unilocular, globose to subglobose, brown; conidiomatal wall comprising 3–4 layers of brown-walled cells of textura angularis. Macroconidiophores lining cavity or limited to a basal layer in some species; usually reduced to conidiogenous cells, rarely septate and branched; commonly invested in mucus. Macroconidiogenesis cells ampulliform, subcylindrical or cylindrical, hyaline, proliferating percurrently. Macroconidia consisting of a body with a basal appendage, delimited by a septum; conidium body unicellular, ellipsoid to fusoid, subcylindrical, globose, broadly ventricose, broadly ellipsoid or broadly fusoid, thick-walled, smooth, brown, with or without pale and dark coloured longitudinal bands, occasionally longitudinally striate, guttulate; basal appendages hyaline, tubular, smooth, thin-walled, often collapsing. Microconidiophores absent or present, in same conidioma, reduced to microconidiogenous cells. Microconidiogenous cells ampulliform or subcylindrical to lageniform, hyaline, smooth, with apical periclinal thickening. Microconidia hyaline, smooth, aseptate, oval to ellipsoid.
Culture characteristics: Colonies spreading, fluffy, with moderate to abundant aerial mycelium, covering plate in 1 mo. On MEA surface dirty white to cream or pale luteous; reverse cream; sometimes sporulating with black conidiomata, oozing black masses. These culture characteristics also apply to the new taxa described below.
Optimal media and cultivation conditions: MEA, PDA and OA under continuous near-ultraviolet light at 25 °C to promote sporulation.
Distribution: Worldwide.
Hosts: On diverse gymnosperm and dicotyledonous hosts, especially on Eucalyptus (Myrtaceae), which is host to 27 of the currently accepted 38 species.
Disease symptoms: Associated with leaf spots, leaf tip dieback or leaf scorch and stem cankers, but pathogenicity has not been established definitively (Crous et al. 2012c).
Notes: Harknessia is characterised by having stromatic to pycnidial conidiomata, and dark brown conidia with tube-shaped basal appendages, longitudinal striations, and rhexolytic secession (Crous et al. 2012c). Sexual morphs were initially described in Cryptosporella (Nag Raj & DiCosmo 1981), which was rejected in favour of the older genus Wuestneia (Reid & Booth 1989). However, the type species of Wuestneia, Wu. aurea (= Wuestneia xanthostroma), was located in the Cryphonectriaceae and was associated with a coelomycete asexual morph having hyaline conidia. Wuestneia is therefore not considered as synonym of Harknessia, and only species placed in the Harknessiaceae and linked to Harknessia morphs were thus transferred to Harknessia (Crous et al. 2012c).
The family Harknessiaceae was introduced based on LSU sequences of taxa belonging to Diaporthales in order to accommodate Harknessia (Crous et al. 2012c).
References: Lee et al. 2004 (morphology and phylogeny); Crous et al. 2012c (morphology and phylogeny).
Etymology: Name refers to Île Bourbon, the original name of La Réunion Island.
Caulicolous and foliicolous, isolated from leaves and twigs incubated in moist chambers (presumed endophyte). Conidiomata up to 300 μm diam, pycnidial, separate to gregarious, subepidermal, becoming erumpent, stromatic, amphigenous, depressed globose; with irregular opening and border of yellowish, furfuraceous cells; conidiomatal wall of textura angularis. Conidiophores reduced to conidiogenous cells lining conidiomatal cavity. Conidiogenous cells 8–10 × 4–8 μm, ampulliform to subcylindrical, hyaline, smooth, invested in mucilage, percurrently proliferating once or twice near apex. Conidia (12–)13–14(–15) × (8–)9–10 μm in vitro, broadly ventricose to ellipsoid, apex subobtusely rounded, aseptate, non-apiculate, yellow-brown, thick-walled, striations in restricted areas, multi-guttulate. Basal appendage (5–)8–12 × 2–2.5 μm in vitro, hyaline, tubular, smooth, thin-walled, devoid of cytoplasm. Microconidia not seen.
Material examined: France, La Réunion, 21°15'5.4"S 55°36'3.3"E, on leaf litter of Eucalyptus robusta (Myrtaceae), 8 Mar. 2015, P.W. Crous & M.J. Wingfield (holotype CBS H-23387, culture ex-type CBS 143913 = CPC 26533).
Notes: Harknessia bourbonica is related to Ha. ravenstreetina, which was also isolated from Eucalyptus leaves. The two species are distinguished in that Ha. ravenstreetina has longer conidia (14−20 μm) that lack striations and has shorter basal appendages (1.5−5 × 2–2.5 μm).
Etymology: Name refers to the host genus, Corymbia.
Caulicolous and foliicolous, isolated from leaves and twigs incubated in moist chambers (presumed endophyte). Conidiomata up to 250 μm diam, pycnidial, separate to gregarious, subepidermal, becoming erumpent, stromatic, amphigenous, depressed globose; with irregular opening and border of yellowish, furfuraceous cells; conidiomatal wall of textura angularis. Conidiophores reduced to conidiogenous cells lining conidiomatal cavity. Conidiogenous cells 6–10 × 4–5 μm, ampulliform to subcylindrical, hyaline, smooth, invested in mucilage, percurrently proliferating once or twice near apex. Conidia (23–)25–28(–30) × (8–)9 μm in vitro, subcylindrical, apex apiculate, aseptate, yellow-brown, thick-walled, lacking striations, granular; in lactic acid some conidia appear to have a central line of paler pigment. Basal appendage (50–)65–80(–100) × 3–4 μm in vitro, hyaline, tubular, smooth, thin-walled, devoid of cytoplasm. Microconidia 3–4 × 1.5–2 μm, hyaline, smooth, guttulate, aseptate, subcylindrical with obtuse ends.
Material examined: Australia, New South Wales, Bom Bom State Forest, on leaf litter of Corymbia maculata (Myrtaceae), 13 Mar. 2017, A.J. Carnegie (holotype CBS H-23388, culture ex-type CPC 33289).
Notes: Harknessia corymbiae was located in a distinct clade distant from the other species of the genus. The only accepted species presently known from Corymbia is Ha. rhabdosphaera. Both species were collected from Australia, but Ha. rhabdosphaera has smaller, striated conidia [(13–)15–17 × (13–)14–15 μm] with short basal appendages (up to 5 μm long).
Etymology: Name refers to the host genus, Cupressus.
Caulicolous and foliicolous, isolated from needles incubated in moist chambers (presumed endophyte). Conidiomata up to 250 μm diam, pycnidial, separate to gregarious, subepidermal, becoming erumpent, stromatic, amphigenous, depressed globose; with irregular opening and border of yellowish, furfuraceous cells; conidiomatal wall of textura angularis. Conidiophores reduced to conidiogenous cells lining conidiomatal cavity. Conidiogenous cells 5–10 × 3–5 μm, ampulliform to subcylindrical, hyaline, smooth, invested in mucilage, percurrently proliferating once or twice near apex. Conidia (20–)21–23(–25) × (8–)9–11(–13) μm in vitro, broadly ventricose, apex apiculate, aseptate, yellow-brown, thick-walled, striations in restricted areas, multi-guttulate. Basal appendage 2–5(–12) × 2–2.5 μm in vitro, hyaline, tubular, smooth, thin-walled, devoid of cytoplasm. Microconidia 4–7 × 3–4 μm, hyaline, smooth, aseptate, broadly ellipsoid.
Materials examined: Spain, Zaragoza, Carretera El Frago, on needles of Cupressus sempervirens (Cupressaceae), 7 Jan. 2016, coll. R. Blasco, det. R.K. Schumacher (holotype CBS H-23389, culture ex-type CBS 143914 = CPC 30192); ibid., CPC 30174.
Notes: Harknessia cupressi was located in an independent clade distant from the other species of the genus. Harknessia cupressi is the only species known from Cupressus sempervirens.
Etymology: Name refers to Eucalyptus pilularis, the host species from which this fungus was isolated.
Caulicolous and foliicolous, isolated from leaves and twigs incubated in moist chambers (presumed endophyte). Conidiomata up to 250 μm diam, pycnidial, separate to gregarious, subepidermal, becoming erumpent, stromatic, amphigenous, depressed globose; with irregular opening and border of yellowish, furfuraceous cells; conidiomatal wall of textura angularis. Conidiophores reduced to conidiogenous cells lining conidiomatal cavity. Conidiogenous cells 4–7 × 2–5 μm, ampulliform to subcylindrical, hyaline, smooth, invested in mucilage, percurrently proliferating once or twice near apex. Conidia (13–)14–16(–20) × (8–)11–12(–13) μm in vitro, globose to rarely broadly ellipsoid, apex obtusely rounded, aseptate, non-apiculate, yellow-brown, thick-walled, striations covering entire conidial body, multi-guttulate. Basal appendage (2–)3–5 × 2–2.5 μm in vitro, hyaline, tubular, smooth, thin-walled, devoid of cytoplasm. Microconidia not seen.
Materials examined: Australia, New South Wales, Pine Creek State Forest, 30.405423S 152.932698E, on leaves of Eucalyptus pilularis (Myrtaceae), 23 Jan. 2017, A.J. Carnegie (holotype CBS H-23391, culture ex-type CPC 33218); ibid., CPC 33356.
Notes: Harknessia pilularis is related to Ha. rhabdosphaera, but Ha. rhabdosphaera produces longer conidiogenous cells (7–15 × 4–6 μm), and wider conidia (13–15 μm).
Authors: Y. Marin-Felix, A.J. Carnegie, M.J. Wingfield, R.K. Schumacher & P.W. Crous