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

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

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).


Harknessia bourbonica

Crous & M.J. Wingf., sp. nov. MycoBank MB824016. Fig. 20.

Fig. 20. Harknessia bourbonica (ex-type CBS 143913). A. Conidioma on OA. B, C. Conidiogenous cells giving rise to conidia. D. Conidia. Scale bars: A = 150 μm, B–D = 10 μm.

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).


Harknessia corymbiae

Crous & A.J. Carnegie, sp. nov. MycoBank MB824017. Fig. 21.

Fig. 21. Harknessia corymbiae (ex-type CPC 33289). A. Conidiomata on OA. B. Conidiogenous cells giving rise to conidia. C, D. Conidia. Scale bars: A = 250 μm, B–D = 10 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).


Harknessia cupressi

Crous & R.K. Schumach., sp. nov. MycoBank MB824018. Fig. 22.

Fig. 22. Harknessia cupressi (ex-type CBS 143914). A. Conidiomata on OA. B, C. Conidiogenous cells giving rise to conidia. D, E. Conidia. Scale bars: A = 250 μm, B–E = 10 μm.

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.


Harknessia pilularis

Crous & A.J. Carnegie, sp. nov. MycoBank MB824020. Fig. 23.

Fig. 23. Harknessia pilularis (ex-type CPC 33218). A. Conidiomata on OA. B, C. Conidiogenous cells giving rise to conidia. D. Conidia. Scale bars: A = 250 μm, B–D = 10 μm.

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