Research Article |
Corresponding author: Miguel A. Bermúdez-Cova ( miguelangelbermudez11@hotmail.com ) Academic editor: Gerhard Rambold
© 2024 Miguel A. Bermúdez-Cova, Tina A. Hofmann, Nourou S. Yorou, Meike Piepenbring.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bermúdez-Cova MA, Hofmann TA, Yorou NS, Piepenbring M (2024) Systematic revision of species of Atractilina and Spiropes hyperparasitic on Meliolales (Ascomycota) in the tropics. MycoKeys 103: 167-213. https://doi.org/10.3897/mycokeys.103.115799
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Atractilina Dearn. & Barthol. and Spiropes Cif. are genera of asexual fungi that comprise species mainly hyperparasitic on black mildews (Meliolales, Ascomycota). Although a common group of anamorphic fungi, they have been described up to now only by morphology and their systematic position is unknown. The present study provides a morphological treatise of all known species of Atractilina and Spiropes hyperparasitic on Meliolales, including insights into their systematic position, based on DNA sequences generated here for the first time. The study was conducted, based on 33 herbarium specimens and 23 specimens recently collected in Benin and Panama. The obtained DNA sequence data (28S rDNA and ITS rDNA) of A. parasitica and of two species of Spiropes show systematic placements in the Dothideomycetes and Leotiomycetes, respectively. The sequence data of the two Spiropes spp. do not group together. Moreover, the anamorph-teleomorph connection between Atractilina parasitica and Malacaria meliolicola, a pseudothecioid fungus, is confirmed. Three species in the genus Spiropes are proposed as new to science, namely S. angylocalycis, S. carpolobiae and S. croissantiformis. Four species are reported for Benin for the first time, three species for Panama and one species for mainland America. Atractilina and Spiropes are currently two genera with highly heterogeneous species and they might have to be split in the future, once the taxonomic concepts are validated by morphology and molecular sequence data.
Anamorph-teleomorph connection, Benin, Dothideomycetes, Hyperparasitism, Leotiomycetes, Panama
Meliolales (Sordariomycetes, Ascomycota) form a large order of biotrophic, obligate plant parasitic fungi in the Tropics and subtropics (
Approximately 200 species of hyperparasitic fungi, i.e. fungi parasitic on other parasites, have been reported to grow on colonies of Meliolales (
Amongst the hyperparasitic fungi, species of the anamorphic genera Atractilina Dearn. & Barthol. and Spiropes Cif. are common hyperparasites of black mildews in the tropics. In the past, they were regarded as conidial stages of Meliolales (
Arthrobotryum Ces., Cercospora Fresen. ex Fuckel, Helminthosporium Link, Pleurophragmium Costantin and Podosporium Schwein. are only a few of the many genera to which species of Atractilina and Spiropes have been assigned in the past, although they were not congeneric with the type specimens of those genera (
There is currently one valid species of Atractilina, namely A. parasitica (G. Winter) Deighton & Piroz. and 19 species of the genus Spiropes known to be hyperparasitic on colonies of Meliolales (
Samples of leaves infected with black mildews were opportunistically collected in western Panama from January-March 2020 and in Benin in February as well as September-October 2022. For the present study, colonies of Meliolales hyperparasitised by Atractilina parasitica and species of Spiropes were considered. Infected leaves were dried in a plant press and deposited in the
Herbarium at the Universidad Autónoma de Chiriquí (
Dried specimens were observed by stereomicroscopy and by light microscopy (LM). Measurements of at least 20 conidia and other structures have been made for each specimen at magnifications of 600× and 1000×. Measurements are presented as mean value ± standard deviation with extreme values in parentheses. Line drawings were made freehand on scaled paper. Scars on conidiophores are drawn in surface view although further cells of the conidiophore are drawn in optical sections. Images and drawings were edited with Photoshop (Adobe, San Jose, California). Specimens were also analysed morphologically by scanning electron microscopy (SEM). Materials used for SEM were prepared according to
Host plants were identified by morphological characteristics and, in some cases, by molecular sequence data. Morphological identifications were made by comparison with herbarium specimens, literature (e.g.
DNA was isolated from the synnemata and hyphae of specimens using the E.Z.N.A Forensic DNA Extraction Kit, following the manufacturer’s instructions. To extract total genomic DNA, a small amount of clean synnemata or single conidiophores were transferred into a sterile Eppendorf tube with approx. 200 μl of distilled water using sterilised tweezers and trying to avoid picking cells of any other organism associated with the leaves and the colonies of black mildews. For example, for the synnemata of Atractilina parasitica and Spiropes melanoplaca, only the upper parts were used for DNA extraction, in order to avoid the basal parts that are in direct contact with cells of other organisms. The samples were frozen for 24 h at -20 °C, and later homogenised for 10–12 min. using a Retsch Mixer Mill MM301 with TL buffer and 2.5 mm Zirconia beads. Isolated DNA was re-suspended in elution buffer and stored at -20 °C.
Two partial nuclear gene regions (ribosomal loci) were amplified and sequenced: For the large subunit nuclear ribosomal DNA (nrLSU, 28S rDNA), the primers LR0R (
Consensus sequences of trace files were generated with Geneious 10.2.2 (https://www.geneious.com,
We also used T-BAS 2.1 (
Based on morphological evidence, the hyperparasitic fungi collected in Panama and Benin are assigned to the genera Atractilina or Spiropes. Amongst these, three species are proposed as new to science, all in the genus Spiropes. Four species represent new reports for Benin and three for Panama. We also present a revision from herbarium material of 17 of the 19 known species of the genus Spiropes and one species of Atractilina hyperparasitic on Meliolales. All species synonyms, unless specified, are taken from
≡ Arthrosporium parasiticum G. Winter, Hedwigia 25: 103, 1886.
≡ Arthrobotryum parasiticum (G. Winter) Hansf., Proc. Linn. Soc. Lond. 155: 64, 1943.
= Isariopsis penicillata Ellis & Everh., Bull. Torrey bot. Club 22: 438, 1895.
≡ Phaeoisariopsis penicillata (Ellis & Everh.) S.C. Jong & E.F. Morris, Mycopath. Mycol. appl. 34: 271, 1968.
= Arthrobotryum tecomae Henn., Hedwigia 43: 397, 1904.
= Arthrobotryum caudatum Syd. & P. Sydow, Etudes sur la Flore du Bas et Moyen Congo 3(1): 22, 1909.
= Arthrobotryum dieffenbachiae F. Stevens, Bot. Gaz. 65: 237, 1918.
= Atractilina callicarpae Dearn. & Barthol., Mycologia 16: 175, 1924.
= Podosporium pallidum Pat., Scient. Surv. P. Rico 8(1) Bot.: 103, 1926.
= Eriomycopsis bosquieae Hansf., Bothalia 4(2): 466, 1942.
= Arthrobotryum deightonii Hansf., Mycol. Pap. 15: 218, 1946.
= Malacaria meliolicola Syd., Annls. Mycol. 28(1/2): 69, 1930. New synonym proposed in this study.
= Paranectria flagellata Hansf., Proc. Linn. Soc. London 153(1): 28, 1941. New synonym proposed in this study.
≡ Malacaria flagellata (Hansf.) Hansf., Mycol. Pap. 15: 128, 1946. New synonym proposed in this study.
Colonies effuse, rust brown or pale brown, with hyphae that form large, erect, dark synnemata clearly visible under the stereomicroscope, but sometimes only loose unstalked tufts around the tips of the setae of the meliolalean host. Hyphae superficial, branched, septate, thin-walled, 1–2.5 µm wide, smooth. Conidiophores may form straw-coloured or pale olivaceous synnemata up to 1.5 mm long, 40 µm wide at the basal stalk-like part. Sometimes the synnemata grow around and up the setae of the meliolalean host. Individual conidiophores straight or sometimes flexuous, cylindrical, 2.5–5 µm thick towards the apex, pale olivaceous brown, with denticles. Conidia solitary, straight or slightly curved, fusiform, truncate at the base, tapering towards the apex and often terminating in a little bulbous swelling, 1 to mostly 3 septate, thin-walled, variable in size, (17–)30–37(–80) × (3.5–)7–8.5 µm, at first more or less colourless, at maturity becoming pale straw coloured, minutely rough-walled. As seen by SEM, the ornamentation of the surface of the conidia is distinctly reticulated, with thin networks and no ridges.
Atractilina parasitica (MB127, MB136) a synnemata (gold spots) on colonies of Meliola sp. (black spots) on a leaf of Opilia celtidifolia b synnemata of (gold spots) on colonies of Meliola clerodendricola (black spots) on a leaf of Clerodendrum capitatum c synnemata d conidiophores drawn in optical section. The thickness of the wall is indicated only in the drawing in the middle e conidia shown in optical section f–i as seen by SEM f conidiophores with denticles g a denticle at the tip of a conidiophore h conidium i bulbous swelling at the tip of a conidium. Scale bars: 1.5 mm (b); 1 mm (c); 5 μm (d,e,i); 8 μm (f); 1 μm (g); 6 μm (h).
On Meliola sp. on living leaves of Opilia celtidifolia (Opiliaceae), Benin, Campus University of Abomey-Calavi, botanical garden, 6°25'7"N, 2°20'34"E, 24 m a.s.l., 9 February 2022, M. A. Bermúdez-Cova, A. Tabé, D. Dongnima, O.P. Agbani, M. Piepenbring, N.S. Yorou, MB127 (UNIPAR, M); on Meliola clerodendricola on living leaves of Clerodendrum capitatum (Lamiaceae), Benin, Abomey-Calavi, Zopah, 6°30'8"N, 2°20'24"E, 37 m a.s.l., 12 February 2022, M. A. Bermúdez-Cova, A. Tabé, D. Dongnima, O.P. Agbani, M. Piepenbring, N.S. Yorou, MB133; on Meliola clerodendricola on living leaves of Clerodendrum capitatum, Benin, Allada, Sékou, 6°38'56"N, 2°11'38"E, 48 m a.s.l., 12 February 2022, M. A. Bermúdez-Cova, A. Tabé, D. Dongnima, O.P. Agbani, M. Piepenbring, N.S. Yorou, MB136 (UNIPAR, M, GenBank accession number: OR804686); on Meliola sp. on living leaves of Pterocarpus santalinoides (Fabaceae), Benin, Lokoli, border of forest, 7°3'41"N, 2°15'26"E, 22 m a.s.l., 20 February 2022, M. A. Bermúdez-Cova, A. Tabé, D. Dongnima, L. Konetche, M. Piepenbring, R. Hounkarin, MB160 (M); on Meliola sp. on living leaves of Coffea arabica (Rubiaceae), Benin, Attogon, Niaouli, CRA-Sud center, 6°44'24"N, 2°8'25"E, 122 m a.s.l., 28 February 2022, M. A. Bermúdez-Cova, A. Tabé, I. Agonglo, M. Piepenbring, N.S. Yorou, O.P. Agbani, MB178 (UNIPAR, M, GenBank accession numbers: OR804685 and OR804687); on Meliola sp. on living leaves of Coffea arabica, Benin, Atlantique, Attogon, Niaouli Forest, 6°44'23"N, 2°8'26"E, 119 m a.s.l., 19 September 2022, A. Krauß, A. Tabé, O. Koukol, N.S. Yorou, AK06H (UNIPAR, M, GenBank accession number: OR804684); on Meliola sp. on living leaves of Clerodendrum capitatum, Benin, Atlantique, Attogon, Pahou Forest, 6°22'56"N, 2°9'35"E, 13 m a.s.l., 6 October 2022, A. Krauß, A. Tabé, O. Koukol, N.S. Yorou, AK61.
On Meliola lasiotricha on leaves of unknown plant host, Puerto Rico, 1926, M.B. Ellis (IMI 130722, type specimen of Podosporium pallidum); On Meliola clerodendri on leaves of Clerodendrum cyrtophyllum, Taiwan, 1938, W. Yamamoto (IMI 31921b, type specimen of Atractilina parasitica).
This species was illustrated by
On colonies of Amazonia spp., Asteridiella spp., Irenopsis spp. and Meliola spp. on living leaves of various plants in Congo, Ghana, Guinea, India, Mauritius, Nigeria, Perú, Philippines, Puerto Rico, Sierra Leone, St. Thomé, Taiwan, Tanzania, Uganda, U.S.A. and Venezuela. Only one single collection on Balladyna sp. (Balladynaceae, Dothideomycetes) as a fungal host (
Only two species of the genus Atractilina with hyperparasitic lifestyle are known, namely A. asterinae and A. parasitica (
The specimens of A. parasitica collected on leaves of Coffea arabica (MB 178, AK4H, AK06H) were found growing together with pseudothecia of Malacaria meliolicola Syd. (Tubeufiales, Dothideomycetes). According to
On Meliola sp. on living leaves of Angylocalyx oligophyllus (Fabaceae), Benin, Atlantique, Attogon, Niaouli Forest, 6°44'42"N, 2°7'50"E, 69 m a.s.l., 28 February 2022, M.A. Bermúdez, A. Tabé, D. Dongnima, I. Agonglo, O.P. Agbani, M. Piepenbring, N.S. Yorou, MB167 (M).
Spiropes armatellae (MB 167) a, b conidiophores growing intermingled with hyphae of Meliola sp. on leaves of Angylocalyx oligophyllus c conidiophore with scars d conidia shown in optical section. The thickness of the wall is shown in the two drawings on the right-hand side e, f as seen by SEM e part of a conidiophore with scar f conidium. Scale bars: 0.3 mm (a); 0.2 mm (b); 5 μm (c, d); 2 μm (e); 7 μm (f).
Named after the genus of the host plant.
Colonies effuse, dark brown to black, velvety to hairy. Hyphae superficial, branched, anastomosing, septate, 0.5–2 µm wide, straw-coloured, smooth. Conidiophores arising singly, erect or ascending, straight to flexuous, mostly flexuous at the tips, septate, up to 350 µm long, 4–6 µm thick, pale olivaceous-brown to brown, with rough surface, with scattered scars mostly in upper parts of the conidiophores. Conidia solitary, straight or slightly curved, fusiform to obclavate, 3–septate, (15–)17–25(–30) × 5–6.5 µm, 2–3 µm wide at the base, brown, the cells at each end pale brown, septa darker in colour, verrucose. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.
On colonies of Meliola sp. on living leaves of Angylocalyx oligophyllus in Benin.
Spiropes angylocalycis is similar to S. clavatus by the presence of 3–septate mostly fusiform conidia, with a similar size range (
On Armatella cinnamomicola on leaves of Cinnamomum sp. (Lauraceae), Sri Lanka, Ceylon, 1971, M.B. Ellis (IMI134405b. The type specimen was not available for loan).
Colonies effuse, dark brown to black, hairy. Hyphae superficial, branched, septate, 1–3 µm wide, straw-coloured, smooth. Conidiophores arising singly, erect or ascending, straight to flexuous, mostly flexuous at their tips, septate, up to 300 µm long, 5–8 µm thick, brown to dark brown, paler towards the apex, with rough surface, with scattered scars in upper parts of the conidiophores. Conidia solitary, straight or slightly curved, obclavate to obpyriform, mostly 1–septate, (20–)30–42(–50) × (6–)7–8(–10) µm, 2–3.5 µm wide at the base, brown, paler towards the ends, verrucose when seen by LM and SEM.
On Armatella litseae on leaves of Daphnidium pulcherrimum (Lauraceae), India, west Bengal, 1967, M.K. Maity (IMI 136371); on Armatella cinnamomicola on leaves of Cinnamomum sp., Myanmar, Thaton, 1971, M.M. Thaung, (IMI 161265).
On colonies of Armatella spp. on various plants in India, Myanmar and Sri Lanka (
This species was illustrated by
Two known species of Spiropes are hyperparasitic on species of the genus Armatella (Meliolales, Armatellaceae), namely S. armatellae and S. armatellicola (
On Armatella sp. on leaves of Actinodaphne sp. (Lauraceae), Banasuran Hills, Wyanad, Kerala, India, 16 April 1999, C.K. Biju (HCIO 43621. The type specimen was not available for loan by HCIO).
This species was described by
On colonies of Armatella sp. on living leaves of Actinodaphne sp. in India (
This species was illustrated by
This species is only known from the type specimen.
≡ Cercospora capensis (Thüm.) Sacc., Syll. fung. 4: 469, 1886.
≡ Helminthosporium capense (Thüm.) [as ‘Helmisporium’], Flora, Regensburg 59: 570, 1876.
≡ Pleurophragmium capense (Thüm.) S. Hughes, Can. J. Bot. 36: 796, 1958.
= Helminthosporium carpocrinum Cif. [as ‘Helmisporium’], Annls. Mycol. 36(2/3): 236, 1938.
= Helminthosporium coffeae Massee [as ‘Helmisporium’], Bull. Misc. Inf., Kew: 167, 1901.
≡ Sporhelminthium coffeae (Massee) Speg., Physis, Rev. Soc. Arg. Cienc. Nat. 4(no. 17): 292, 1918.
= Helminthosporium fici H.S. Yates [as ‘ficuum’], Philipp. J. Sci. (Bot.) 13: 382, 1918.
= Helminthosporium ficinum Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr., Sér. 3, 10: 90, 1919.
= Helminthosporium fumagineum Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr., Sér. 3, 10: 90, 1919.
= Helminthosporium filicicola Henn., Hedwigia 44: 71, 1905.
= Helminthosporium glabroides F. Stevens [as ‘Helmisporium’], Bot. Gaz. 65(3): 240, 1918.
= Helminthosporium melioloides Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr., Sér. 3, 10: 89, 1919.
= Helminthosporium orbiculare Lév., Annls. Sci. Nat., Bot., Sér. 3, 5: 299, 1846.
= Helminthosporium philippinum Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr., Sér. 3, 10: 89, 1919.
= Helminthosporium subsimile Sacc., Boll. Orto bot., Napoli 6: 23, 1921.
= Helminthosporium tapurae Allesch., Hedwigia 36(4): 245, 1897.
= Napicladium portoricense Speg., Boln Acad. nac. Cienc. Córdoba 26(2–4): 363, 1921.
≡ Helminthosporium portoricense (Speg.) Cif., Sydowia 9(1–6): 298, 1955.
= Nascimentoa pseudoendogena Cif. & Bat., Publicações Inst. Micol. Recife 44:4, 1956.
Colonies
effuse, dark brown to black, hairy (
Spiropes capensis (AK06H) a, b groups of conidiophores growing on hyphae of Meliola sp c conidiophores growing on hyphae of Meliola sp. shown in optical section d conidia shown in optical section. The thickness of the outer wall layer is indicated only in the drawing on the right-hand side e, f as seen by SEM e conidiophores with scars f conidia. Scale bars: 1 mm (a, b); 8.5 μm (c); 5 μm (d); 5 μm (e); 20 μm (f).
On Meliola sp. on living leaves of Coffea arabica, Benin, Atlantique, Attogon, Niaouli Forest, 6°44'23"N, 2°8'26"E, 119 m a.s.l., 19 September 2022, A. Krauß, A. Tabé, O. Koukol, N.S. Yorou, AK06H.
– On leaves of Ficus ulmifolia (Moraceae), Philippines, Los Baños, 1915, C.F. Baker, 451 (IMI 130940, type of Helminthosporium fumagineum); on Meliola compositarum on leaves of Eupatorium portoricense (Asteraceae), Puerto Rico, Bega Vaja, 1921, no. 1753 (IMI 100331a, type of Napicladium portoricense).
On colonies of Appendiculella spp., Asteridiella spp., Irenopsis spp. and Meliola spp. on living leaves of various plants in Amboina, Bolivia, Brazil, Cameroon, Congo, Dominican Republic, Ghana, India, Jamaica, Malaya, Peru, Philippines, Puerto Rico, Sabah, Sierra Leone, South Africa, Tanzania, Trinidad, Uganda and Venezuela (
This species was illustrated by
According to the nomenclatural and taxonomic database Index Fungorum (http://www.IndexFungorum.org), the current name of the Spiropes capensis is Pleurophragmium capense (Thüm.) S. Hughes. The genus Pleurophragmium (incertae sedis, Ascomycota) was established by
Colonies effuse, dark brown to black, velvety to hairy. Hyphae superficial, branched, septate, 1.5–3.5 µm wide, pale olivaceous-brown, smooth. Conidiophores arising singly, erect or ascending, straight or flexuous, septate, up to 240 µm long, 4–8 µm thick, pale brown to brown, smooth, with few scars. Conidia solitary, straight or slightly curved, obclavate, central cells barrel-shaped, 3-septate, (30–)36–48(–41.5) × (7.5–)9.5–11.5 µm, 4.5–6 µm wide at the truncate base, the central cells pale brown, the cells at the ends paler and almost hyaline, smooth.
On Meliola sp. on leaves of an unknown palm-tree, Cuba, Isla de La Juventud (= Isla de Pinos), Los Indios, south-west of La Cañada, 1981, V. Holubová-Jechová (PRM 831531, holotype).
On Meliola sp. on living leaves of an unidentified palm tree in Cuba (
This species was illustrated by
Spiropes caribensis is similar to S. helleri, but differs from the latter by paler conidia, with wider truncate base (S. helleri has conidia with a truncate base 3–4 µm wide) and shorter conidiophores (up to 600 µm long in S. helleri;
On Meliola cf. carpolobiae on living leaves of Carpolobia lutea (Polygalaceae), Benin, Atlantique, Attogon, Niaouli Forest, 6°44'41"N, 2°7'52"E, 68 m a.s.l., 28 February 2022, M.A. Bermúdez, A. Tabé, D. Dongnima, I. Agonglo, O.P. Agbani, M. Piepenbring, N.S. Yorou, MB166 (M).
Spiropes carpolobiae (MB 166) a conidiophores growing intermingled with hyphae of Meliola sp. on a leaf of Carpolobia lutea b conidiophore with scars c Conidia shown in optical section. The thickness of the wall is shown in the left-hand drawing d, e as seen by SEM d conidiophore with scar e conidium. Scale bars: 0.3 mm (a); 5 μm (b, c); 5 μm (d); 3 μm (e).
Named after the genus of the host plant.
Colonies effuse, dark brown to black, velvety to hairy. Hyphae superficial, branched, anastomosing, septate, 1–2 µm wide, straw-coloured, smooth. Conidiophores arising singly, erect or ascending, straight to flexuous, septate, up to 250 µm long, 2–5 µm thick, sometimes thicker at the apex, brown, not smooth, with scattered scars mostly in the upper parts of the conidiophores. Conidia solitary, straight or slightly curved, ovate to slightly fusiform, 3–septate, (12.5–)13–16(–19) × 5–7 µm, 2–2.5 µm wide at the base, brown, the cells at each end pale brown, septa darker, surface verrucose. As seen by SEM, the ornamentation of the conidia is distinctly reticulated, with thin to thick networks that can form ridges.
On colonies of Meliola cf. carpolobiae on living leaves of Carpolobia lutea in Benin.
S. carpolobiae is the only known species of Spiropes with ovate to slightly fusiform conidia.
≡ Isariopsis clavata Ellis & Martin, Am. Nat. 18: 188, 1884.
≡ Arthrobotryum clavatum (Ellis & Martin) Höhn, Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1, 125: 120, 1916.
≡ Bitunicostilbe clavata (Ellis & Martin) M. Morelet, Bull. Soc. Sci. nat. Arch. Toulon et du Var 7: 195, 1971.
= Podosporium chlorophaeum Speg., An. Mus. nac. Hist. nat. B. Aires 20: 450, 1910.
= Arthrobotryum noz-moscatae Bat. & J. Silva, Anais IV Congr. Soc. bot. Brasil: 144, 1953.
Colonies effuse, brown to dark brown or black. Hyphae superficial, branched, anastomosing, septate, 1–3 µm wide, pale olivaceous-brown. Conidiophores tightly packed to form dark brown to blackish synnemata up to 700 µm long, 20–40 µm thick, often splaying out to a width of up to 110 µm at the apex. Individual hyphae straight or flexous, cylindrical, 1–3 µm thick near the base, 4–7 µm thick near the apex, dark brown, paler towards the apex, verrucose, with numerous conidial scars. Conidia solitary, fusiform to obclavate, mostly 3–, rarely 1–, 2– or 4–septate, (13–)18–25(–33) × (4–)5–7(–8) µm, tapering to about 1–1.5 µm at the apex and at the base, pale brown to brown, the cells at each end paler, wrinkled. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.
On Meliola panici on leaves of Panicum glutinosa, Puerto Rico, El Alto de la Bandera, 1913, F.L. Stevens & W.E. Hess, n°4368 (IMI 130764); on Meliola sp. on leaves of Raphia monbuttorum, Uganda, 1915, R. Dümmer, (IMI 102772); on Meliola thouiniae on leaves of an unknown plant, Brasil, São Paulo, 1940, A.R. Campos (IMI 130975, type of Arthrobotryum noz-moscatae).
This species was illustrated by
On colonies of Meliolales on living leaves of various plants in Argentina, Brazil, Ghana, Malaysia, Puerto Rico, Sierra Leone, Trinidad and Uganda (
In the nomenclatural and taxonomic database Index Fungorum (http://www.IndexFungorum.org), the current name of the Spiropes clavatus is Bitunicostilbe clavata (Ellis & Martin) M. Morelet. The genus Bitunicostilbe (incertae sedis, Ascomycota) was proposed by
On Meliola cf. xylopiae on living leaves of Xylopia frutescens, Panama, Chiriquí Province, Cochea, Cochea River Trail, 8°32'37"N, 82°23'03"W, 181 m a.s.l., 26 February 2020, M.A. Bermúdez, A. Sanjur, A. Villarreal, MB110 (
Named after the shape of the conidia.
Colonies effuse, dark brown to black, with tightly packed hyphae that form erect, dark synnemata clearly visible under the stereomicroscope. Hyphae superficial, branched, septate, 1–2 µm wide, straw-coloured, smooth. Conidiophores tightly packed to form dark brown to blackish synnemata up to 400 µm high, spreading out at the apex, up to 80 µm diam. Individual hyphae mostly straight, cylindrical, 3–5 µm thick, with numerous small scars, brown, paler towards the apex, rough. Conidia straight or curved, mostly crescent-shaped, sometimes fusiform, mostly 3(–5)–septate, (14–)20–24(–33) × (3.5–)5–6.5 µm, with two golden brown middle cells and paler cells at each. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.
On colonies of Meliola cf. xylopiae on living leaves of Xylopia frutescens (Annonaceae) in Panama.
Spiropes xylopiae is a synnematous hyperparasitic species of Spiropes with the shortest synnemata (up to 400 µm), when compared to other synnematous species, such as S. melanoplaca with synnemata that can reach up to 1.5 mm and S. penicillium with synnemata up to 700 µm high. In addition to this, the new species has crescent-shaped conidia, a feature that is not present in any other known species of the genus.
Spiropes croissantiformis (MB 110) a synnemata (indicated by white arrows) growing on colonies of Meliola cf. xylopiae b synnema (indicated by a black arrow) c conidiophores with scars and young conidia, shown in optical section d conidia shown in optical section. The thickness of the wall is only shown for the first spore from the left e, f as seen by SEM e part of a conidiophore with scars f conidia. Scale bars: 160 μm (a); 400 μm (b); 5 μm (c, d); 5 μm (e); 10 μm (f).
Colonies effuse, olive to olivaceous-brown, velvety or hairy. Hyphae superficial, branched, septate, 0.5–2 µm wide, pale olive to olivaceous-brown, smooth. Conidiophores arising singly or in groups terminally or laterally from the hyphae, erect or ascending, straight or flexous, septate, up to 400 µm long, 2–4 µm thick along most of their length, swollen towards the apex, 5–8 µm thick, brown, reticulate as seen by SEM, with scattered cylindrical scars. Conidia solitary, straight or slightly curved, obovate to clavate, truncate at their base, 3–septate, (10–)12–14(–15) × (5–)6–8 µm, 1.5–2 µm wide at the base, the cells at each end of a conidium subhyaline or pale brown, intermediate cells brown, ornamented. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks that can form ridges.
On Meliola borneensis on Uvaria chamae, Sierra Leone, 1951, F.C. Deighton, (IMI 48956a, type of S. deightonii).
This species was illustrated by
On colonies of Meliola borneensis on living leaves of Uvaria chamae (Annonaceae) in Sierra Leone (
Spiropes deightonii and Spiropes intricatus are the only known species of the genus that present conidiophores that swell in the areas where conidia are formed (Figs
Spiropes deightonii (IMI48956a) a conidiophores b conidia, as seen by LM (two upper spores; the thickness of the wall is indicated only in the drawing on the left-hand side) and by SEM (bottom spore) c, d as seen by SEM c conidiophore d conidia. Scale bars: 5 μm (a, b); 8 μm (c); 5 μm (d).
≡ Helminthosporium dorycarpum Mont., Annls Sci. nat., 2 Sér., 17: 120, 1842.
≡ Pleurophragmium dorycarpum (Mont.) Hughes, Can. J. Bot. 36: 797, 1958.
= Helminthosporium orbiculare Lév., Annls Sci. nat., 3 Sér., 5: 299, 1846.
= Napicladium myrtacearum Speg., An. Soc. cient. Argent. 26: 71, 1888.
≡ Sporhelminthium myrtacearum (Speg.) Speg., Physis 4(17): 292, 1918.
= Helminthosporium conspicuum McAlpine, Proc. Linn. Soc. N.S.W. 22: 40, 1897.
= Podosporium densum Pat., J. Bot. Paris 11: 373, 1897.
= Helminthosporium asterinoides Sacc. & P. Syd., apud Saccardo, Rc. Congr. Bot. Palermo, May 1902: 58, 1902.
≡ Sporhelminthium asterinoides (Sacc. & Syd.) Speg., Physis 4(17): 292, 1918.
= Helminthosporium melastomacearum F. Stevens, Bot. Gaz. 65: 242, 1918.
= Helminthosporium panici F. Stevens, Bot. Gaz. 65: 242, 1918.
= Helminthosporium parathesicola [as ‘parathesicolum’] F. Stevens, Bot. Gaz. 65: 242, 1918.
Colonies effuse, brown to dark brown, hairy. Hyphae superficial, branched, septate, 1–3 µm wide, straw-coloured, pale brown, smooth. Conidiophores arising singly or in groups, terminally or laterally from the hyphae, erect or ascending, straight or flexous, septate, up to 700 µm long, 3–7 µm thick, straw-coloured, pale brown to brown, with scattered cylindrical scars towards the apex. Conidia solitary, straight or slightly curved, variable in shape, but mostly obclavate to fusiform, truncate at the base, mostly 3–septate, but sometimes with 4 to 5 septa, (16–)20–35(–40) × (4.5–)5–7 µm, straw-coloured to pale brown, middle cells slightly darker, wrinkled or verrucose. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.
On Meliola sp. on living leaves of Coffea arabica, Benin, Atlantique, Attogon, Niaouli Forest, 6°44'23"N, 2°8'26"E, 119 m a.s.l., 19 September 2022, A. Krauß, A. Tabé, O. Koukol, N.S. Yorou, AK06H.
On Eugenia pungens, Brasil, Guarapí, 1883, B. Balansa, 3939, (IMI 100322, type of Napicladium myrtacearum); on Meliola sp. on leaves of an unknown plant, Cuba, R. de la Sagra (IMI 10002, type of Helminthosporium dorycarpum).
This species was illustrated by
On colonies of Appendiculella spp., Asteridiella spp., Clypeolella spp., Irenopsis spp., Meliola spp. and Schiffnerula spp., on living leaves of various plants in Australia, Brazil, Chile, Congo, Cuba, Dominican Republic, Ghana, Guyana, India, Malaysia, Nigeria, Puerto Rico, Sierra Leone, South Africa, Taiwan, Tanzania and Uganda (
Spiropes dorycarpus (AK06H) a superficial hyphae growing on a colony of Meliola sp. on a leaf of Coffea arabica b, c in optical section b conidiophore growing on a hypha of Meliola sp. c conidia. The thickness of the wall is indicated only in the drawing on the left-hand side d, e As seen by SEM d conidiophore with a scar e conidium. Scale bars: 1 mm (a); 5 μm (b); 3.5 μm (c); 3 μm (d); 7 μm (e).
Spiropes dorycarpus is similar to S. effusus and S. helleri by the presence of non-synnematous conidiophores and conidia mostly with three true septa. However, conidia of S. effusus are narrower (3–5 µm) than those of S. helleri (7–13 µm).
≡ Podosporium effusum Pat., Scient. Surv. P. Rico 8(1): 103, 1926.
= Helminthosporium dorycarpum var. amazoniae Hughes [as ‘Helmisporium’], Mycol. Pap. 50: 24, 1953.
≡ Pleurophragmium dorycarpum var. amazoniae (S. Hughes) S. Hughes, Can. J. Bot. 36: 797, 1958.
Colonies effuse, olive to brown, hairy. Hyphae superficial, branched, septate, 1–2 µm wide, yellowish, olive or pale brown, smooth. Conidiophores arising singly or in groups, as terminal and lateral branches on the hyphae, erect, straight or flexous, septate, up to 300 µm long, 3–4 µm thick, slightly reticulated when seen by SEM, with few or many small conidial scars towards the apex. Conidia solitary, narrowly obclavate to fusiform, truncate at the base, mostly 3(–5)–septate, (15–)20–36 × (3–)3.8–4.5(–5) µm, pale brown, the central cells slightly darker, verruculose. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin networks and no ridges.
On meliolalean fungus on leaves of Piper sp., Puerto Rico, Río Piedras, 1926, Heller, 142 (IMI 130721, type of Podosporium effusum); on Amazonia psychotriae on leaves of Psychotria warneckei, Ghana, Togoland, 1938, F.C. Deighton M1617B (IMI 9996a).
This species was illustrated by
On colonies of Meliolales, especially Amazonia spp., on living leaves of various plants in Ghana, Puerto Rico, Sierra Leone and Venezuela. One record on Asterina sp. (Asterinales, Ascomycota) in Uganda (
Spiropes effusus (IMI 130721) a conidiophore shown in optical section b conidia. The first two drawings show spores in optical section. The right-hand drawing shows a conidium as seen by SEM c, d as seen by SEM c conidiophore with scars and conidia d conidium. Scale bars: 5 μm (a); 8 μm (b); 2 μm (c); 8 μm (d).
Spiropes effusus has conidia similar in size to those of S. dorycarpus. However, conidia of S. dorycarpus are wider (5–7 µm) than in S. effusus.
≡ Helminthosporium fumosum Ellis & Martin, Am. Nat. 18: 70, 1884.
≡ Brachysporium fumosum (Ellis & Martin) Sacc., Syll. Fung. 4: 428, 1886.
On Meliola sp. on leaves of Persea palustris (Lauraceae), Florida, U.S.A, 1883, G. Martin (NY 830274. The type specimen was not available for loan by NY).
This species was described by
On colonies of Meliola sp. on living leaves of Persea palustris in the U.S.A. (
On Meliolales on living leaves of Persea palustris, U.S.A, Florida, Cove Springs, 1890, G. Martin, (IMI 16307).
This species was illustrated by
The specimen IMI 16307 was analysed, but no fungal cells were seen.
≡ Helminthosporium guareicola F. Stevens [as ‘Helmisporium guareicolum’], Bot. Gaz. 65(3): 241, 1918.
≡ Pleurophragmium guareicola (F. Stevens) S. Hughes, Can. J. Bot. 36: 797, 1958.
= Cladosporium elegans var. singaporense Sacc., Bull. Orto Bot. Regia Univ. Napoli 6: 60, 1921.
= Helminthosporium flagellatum H.S. Yates [as ‘Helmisporium’], Philipp. J. Sci. (Bot.) 13: 383, 1918.
= Helminthosporium spirotrichum Sacc. [as ‘Helmisporium’], Boll. Orto bot. 6: 61, 1921.
Colonies effuse, dark brown to black, hairy. Hyphae superficial, branched, septate, 2–4 µm wide, pale olivaceous-brown, smooth. Conidiophores arising singly or in groups, as lateral branches on the hyphae, erect, sterile lower part straight or flexuous, upper fertile part in zigzag shape, septate, up to 400 µm long, 6–9 µm thick, brown to dark brown, paler towards the apex, more or less smooth, with numerous well-defined, dark conidial scars. Conidia solitary, broadly fusiform, truncate at the base, with 3 to 5 pseudosepta, (25–)35–52(–60) × (7–)8–10(–13) µm, 3.5–5 µm wide at the base, pale to dark brown or olivaceous-brown, smooth as seen by SEM.
On leaves of Cyrtophyllum fragrans (Gentianaceae), Singapore, 1921, Baker (IMI 49160, type of Helminthosporium spirotrichum); on Meliola sp. on leaves of Daniellia thurifera (Fabaceae), Sierra Leone, 1936, F.C. Deightonii M1267 (IMI 10010).
This species was illustrated by
On colonies of Asteridiella spp., Irenopsis spp. and Meliola spp. on living leaves of various plants in Bougainville Islands, Ghana, India, Indonesia, Malaysia, Philippines, Puerto Rico, Sabah, Sierra Leone, Solomon Islands and Uganda (
Spiropes guareicola (IMI 10010) a conidiophore with scars and a young conidium shown in optical section b base of a conidiophore growing on a hypha of Meliola sp. shown in optical section c conidia shown in optical section (two drawings on the left-hand side) and as seen by SEM (two drawings on the right-hand side) d, e as seen by SEM d zigzag-shaped conidiophore with scars e conidium. Scale bars: 5 μm (a–c); 8 μm (d); 10 μm (e).
Spiropes guareicola is the type species of the genus Spiropes and it differs from other species of the genus by the presence of zigzag-shaped conidiophores in the fertile upper parts (
≡ Helminthosporium helleri F. Stevens [as ‘Helmisporium], Bot. Gaz. 65(3): 242, 1918.
= Helminthosporium leucosykes H.S. Yates [as ‘Helmisporium leucosykeae’], Philipp. J. Sci., C, Bot. 13(6): 382, 1918.
= Helminthosporium maculosum Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr. 10: 91, 1919 [1917].
≡ Pleurophragmium maculosum (Sacc.) S. Hughes, Can. J. Bot. 36: 797, 1958.
Colonies effused, dark brown to black, hairy. Hyphae superficial, branched, septate, 1–3 µm wide, straw-coloured or pale brown, smooth. Conidiophores arising singly as terminal or lateral branches on the hyphae, erect, straight or flexuous, septate, up to 600 µm long, 5–8 µm wide, brown to dark brown, paler towards the apex, smooth, with scattered conidial scars. Conidia solitary, obclavate, frequently rostrate, 3(–4)–septate, (26–)36–43(–50) × (6–)7–10(–13) µm, 3–4 µm wide at the truncate base, pale brown to brown, verruculose. As seen by SEM, the ornamentation of the spores is clearly reticulated, with thin networks and no ridges.
On Meliola sp. on leaves of Cupania guatemalensis (Sapindaceae), Panama, Chiriquí Province, Botanical Garden of the Autonomous University of Chiriquí (UNACHI), 8°25'55"N, 82°27'03"W, 34 m a.s.l., 11 February 2020, M. A. Bermúdez-Cova, A. Sanjur MB92 (UCH15489, M); on Meliola sp. on living leaves of Pterocarpus santalinoides (Fabaceae), Benin, Atlantique, Attogon, Niaouli Forest, 6°44'40"N, 2°7'53"E, 72 m a.s.l., 20 September 2022, A. Krauß, A. Tabé, O. Koukol, N.S. Yorou, AK15 (M).
On Meliolales on living leaves of an undetermined plant, Gold Coast Colony, Banau, 1949, S.J. Hughes 1141 (IMI44564); on Meliola sp. on leaves of Myrcia deflexa, Puerto Rico, El Alto de la Bandera, F.L. Stevens 8268 (IMI9991, type of Helminthosporium helleri).
This species was illustrated by
On colonies of Asteridiella spp., Irenopsis spp. and Meliola spp. on living leaves of various plants in Ghana, Malaysia, New Caledonia, Philippines, Puerto Rico, Sabah, Sierra Leone and Uganda (
Spiropes helleri (IMI130940) a superficial hyphae growing on a colony of Meliola sp. on a leaf of Cupania guatemalensis b conidiophore growing on a hypha of Meliola sp. shown in optical section c conidia shown in optical section (drawing on the left-hand side) and as seen by SEM (drawing on the right-hand side) d, e as seen by SEM d part of a conidiophore with a scar e conidium. Scale bars: 1 mm (a); 5 μm (b); 6 μm (c); 4 μm (b); 5 μm (c).
Spiropes helleri is similar to S. effusus, S. dorycarpus and S. leonensis by the presence of obclavate to sometimes fusiform conidia, but differs from the first two by wider conidia (3.8–4.5 µm in S. effusus and 5–7 µm in S. dorycarpus) and from the last one by narrower ones (10–11µm).
≡ Brachysporium intricatum Sacc., Atti Accad. scient. Veneto-trent.-istriana, Ser. 3, 10: 88, 1919.
= Spiropes pirozynskii M.B. Ellis, Mycol. Pap. 114: 19, 1968. New synonym proposed in this study.
Colonies effuse, straw-coloured, olive or olivaceous-brown, velvety or hairy. Hyphae superficial, branched, anastomosing, septate, 1–2 µm wide, pale olivaceous brown, smooth. Conidiophores arising singly or in groups, terminally or laterally from the hyphae, erect or ascending, straight or flexuous, septate, up to 900 µm long, 2–5 µm thick along most of their length, swollen to 4–9 µm towards the apex and in intercalary parts that produce conidia, pale olivaceous-brown to brown, reticulate as seen by SEM, with scattered cylindrical scars. Conidia solitary, straight or slightly curved, oblong-ellipsoid or obovate to clavate, truncate at the base, mostly 3–septate, (13–)16–23(–25) × (4.5–)6–8 µm, 1.5–3 µm wide at the base, the cells at each end of a conidium pale brown, intermediate cells brown, ornamented. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks that can form ridges.
On Irenopsis sp. on Lindackeria bukobensis (Achariaceae), Tanzania, Kigoma, 1964, K.A. Pirozynski M418 b&c (IMI 106645b-c, type of Spiropes pirozynskii); on leaves of Camellia drupifera (Theaceae), Nepal, Kathmandu, Godawari, 1986, U. Budathoki KU294 (IMI323287).
This species was illustrated by
On colonies of Meliolales on living leaves of various plants in Ghana, Philippines and Tanzania (
Spiropes intricatus and S. deightonii are the only known species of the genus that present conidiophores that swell in the areas where conidia are formed (Figs
Spiropes intricatus (IMI 106645b-c) a conidiophores, growing on a hypha of Irenopsis sp., shown in optical section b conidia shown in optical section (the thickness of the wall is indicated only in the drawings on the upper row) and as seen by SEM (second row right) c, d as seen by SEM c conidiophore with scars d conidium. Scale bars: 5 μm (a); 3 μm (b); 7 μm (c); 8 μm (c).
≡ Podosporium japonicum Henn., Bot. Jb. 29: 152, 1900.
= Helminthosporium insigne Gaillard ex Sacc. [as ‘Helmisporium’], Atti Accad. Sci. Ven.-Trent.-Istr. 10: 89, 1917.
Colonies effuse, amphigenous, sometimes dense, dark brown to black, with tightly packed hyphae that form large, erect, dark synnemata clearly visible under the stereomicroscope. Hyphae superficial, branched, septate, 1–4 µm wide, pale olivaceous-brown, smooth. Conidiophores tightly packed to form dark brown to blackish synnemata up to 1 mm high, spreading out at the apex and upper half of the synnemata; conidiophores individually flexuous or straight, thick-walled, septate, 6–8 µm thick, brown to dark brown at the base, paler towards the apex, smooth, with scattered cylindrical scars. Conidia solitary, fusiform to obclavate, with 4(–6) pseudosepta, (50–)67–80 × (7–)8–14 µm, 2–3 µm wide at the apex, 3–5 µm at the truncate base, pale brown to brown, striate.
Spiropes japonicus (MB120, 123) a synnemata growing on a colony of Meliola sp. b conidiophores with scars and a young conidium, shown in optical section c a conidium shown in optical section (drawing on the left) and as seen by SEM (drawing on the right) d, e as seen by SEM d conidiophore with a scar e conidium. Scale bars: 1 mm (a); 10 μm (b, c); 3 μm (d); 9 μm (d).
On Meliola sp. on living leaves of Asteraceae, Panama, Chiriquí Province, Boquerón District, Chuspa Hydroelectric, 8°32'20"N, 82°36'21"W, 281 m a.s.l., 6 March 2020, M. A. Bermúdez-Cova, A. Sanjur, S. Samaniego, MB120 (UCH15492); on Meliola sp. on living leaves of Fabaceae, Panama, Chiriquí Province, Bugaba District, area around Gariché River, 8°38'38.1"N, 82°41'19.6"W, 566 m a.s.l., 8 March 2020, M. A. Bermúdez-Cova, A. Sanjur, A. Villarreal, MB123 (UCH15493, M).
On Irenina entebbeensis on Alchornea hirtella (Euphorbiaceae), Sierra Leone, 1939, Makump, M1774 (IMI 38813); on Asteridiella aucubae on Aucuba japonica (Garryaceae), Japan, Ise, 1899, P. Hennings (IMI 130973, type of Podosporium japonicum).
This species was illustrated by
On colonies of Meliolales on living leaves of various plants in the Cook Islands, Japan, Malaysia, Papua New Guinea and Sierra Leone (
Spiropes japonicus is the only known synnematous species of Spiropes that produces conidia with 4–6 pseudosepta, as well as synnemata that splay out at the apex and upper half (
Colonies effuse, grey to dark blackish-brown, hairy. Hyphae superficial, branched, septate, 2–6 µm wide, pale brown, smooth. Conidiophores arising singly, as terminal and lateral branches on the hyphae, erect, straight or flexuous, septate, up to 700 µm long, 8–12 µm thick, sometimes swollen to 16–17 µm at the base, dark brown to dark blackish-brown, paler towards the apex, smooth, with scattered conidial scars. Conidia solitary, obclavate, rostrate, 3(–4)–septate, (38–)40–54(–63) × (8–)10–11(–13) µm, 4–6 µm wide at the truncate base, pale brown to brown, verruculose. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin networks and no ridges. It was not possible to see the scars by SEM.
On Meliola garciniae on leaves of Pentadesma butyracea (Clusiaceae), Sierra Leone, Rokupr, 1951, F.C. Deighton M3920 (IMI 46589b, holotype); on Meliola garciniae on Pentadesma butyracea, Sierra Leone, near Rokupr, 1939, F.C. Deighton (IMI 9992a, type of Spiropes leonensis).
This species was illustrated by
On colonies of Meliola garciniae on living leaves of Pentadesma butyracea (Clusiaceae) in Sierra Leone (
Spiropes leonensis (IMI 46589b) a conidiophore with scars and a young conidium, shown in optical section b part of a conidiophore growing on a hypha of Meliola sp., shown in optical section c conidia shown in optical section (first two drawings, from left to right) and as seen by SEM d conidium as seen by SEM. Scale bars: 8.5 μm (a–c); 7 μm (d).
Spiropes leonensis is similar to S. helleri by the presence of rostrate, obclavate, 3–septate conidia (
= Arthrobotryum melanoplaca Berk. & M.A. Curtis, J. Linn. Soc. Bot. 10(46): 360, 1868.
≡ Podosporium melanoplaca (Berk. & M.A. Curtis) Cif., Sydowia 9(1–6): 310, 1955.
= Podosporium dialii Bat. [as ‘dialiumii’], Atas Inst. Micol. 1: 266, 1960. New synonym proposed in this study.
≡ Spiropes dialii (Bat.) M.B. Ellis, Mycol. Pap. 114: 27, 1968. New synonym proposed in this study.
= Arthrobotryum scoparium Henn., Hedwigia 43(6): 397, 1904. New synonym proposed in this study.
Colonies effuse, dark brown to black, hairy, with tightly packed hyphae that form large, erect, dark synnemata clearly visible under the stereomicroscope. Hyphae superficial, branched, septate, 1.5–6 µm wide, pale olivaceous, smooth. Conidiophores tightly packed to form dark brown to blackish synnemata up to 1.5 mm high, spreading out at the apex, 20–80 µm thick, splaying out at the apex. Individual hyphae straight or flexuous, cylindrical, 2–6 µm thick along most of their length, 5–8 µm thick near the apex, with numerous small scars that may overlap like scales. As evident by SEM, the scales are produced by the peeling of the outer wall layers where the scars are located. Conidia straight or curved, fusiform to obclavate, 3-septate, (30–)40–52(–68) × (7–)9–11(–14) µm, with the two middle cells usually golden brown or brown, warty and the cells at each end paler. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.
On Meliola mangiferae on living leaves of Mangifera indica (Anacardiaceae), Panama, Chiriquí Province, Los Algarrobos, 8°31'05"N, 82°25'25"W, 168 m a.s.l., 20 January 2020, M. A. Bermúdez-Cova, MB81; same fungal and plant host, Panama, Chiriquí Province, Universidad Autónoma de Chiriquí (UNACHI), 8°25'57"N, 82°27'02"W, 37 m a.s.l., 23 January 2020, M. A. Bermúdez-Cova, MB85 (UCH15487); same fungal and plant host, Panama, Chiriquí Province, Los Algarrobos, Majagua River Trail, 8°28'56"N, 82°24'47"W, 101 m a.s.l., 23 January 2020, M. A. Bermúdez-Cova, MB89 (UCH15488, M); same fungal and plant host, Panama, Chiriquí Province, Meseta de Chorcha, 8°24'19"N, 82°13'26"W, 94 m a.s.l., 16 February 2020, M. A. Bermúdez-Cova, A. Sanjur, MB101 (
On Meliola mangiferae on Mangifera indica, Brunei, 1974, W.T.H. Peregrine (IMI189570a); on Meliola sp. on Psychotria sp. (Rubiaceae), Cuba, 1879, C. Wright (IMI 105348 and IMI 105349, syntypes of Arthrobotryum melanoplaca).
This species was illustrated by
On colonies of Meliolales, especially Meliola spp., on living leaves of various plants in Brazil, Cuba, China, Dominican Republic, Ghana, Guadalcanal, India, Malaysia, Peru, Philippines, Sierra Leone, Tanzania, Trinidad and Uganda (
Spiropes melanoplaca (MB81, MB119, IMI189570a) a, b synnemata growing on hyphae of Meliola mangiferae on living leaves of Mangifera indica c conidiophores with scars and young conidia shown in optical section. The thickness of the wall is only shown in the first conidiophore, from left to right d conidia, shown in optical section (left-hand drawing) and as seen by SEM (right-hand drawing) e, f as seen by SEM e parts of conidiophores with scars f conidium. Scale bars: 1.5 mm (a); b); 0.9 mm (c); 8 μm (d); 7 μm (e); 8 μm (f).
According to
≡ Helminthosporium palmetto W.R. Gerard, Grevillea 17(83): 68, 1889.
≡ Pleurophragmium palmetto (W.R. Gerard) S. Hughes, Can. J. Bot. 36: 778, 1958.
Colonies effuse, dark brown to black, hairy. Hyphae superficial, branched, anastomosing, septate, 1–4 µm wide, pale olivaceous-brown, smooth. Conidiophores arising singly or in groups, as terminal and lateral branches on the hyphae, erect, straight or flexuous, septate, up to 400 µm long, 6–10 µm thick, dark brown, paler towards the apex, smooth, with scattered conidial scars. Conidia solitary, obclavate to fusiform, rostrate, with 2 septa delimiting a barrel-shaped central cell and often with an additional dark central pseudoseptum, (27–)30–46 × (7–)9–12(–15) µm, 3–5 µm wide at the truncate base, brown, middle cells pale brown, smooth as seen by LM and SEM.
On Meliola sp. on leaves of Elaeis guineensis (Arecaceae), Ghana, Apremodo, 1949, S.J. Hughes 534 (IMI 38617); on Meliola sp. on leaves of Sabal palmetto (Arecaceae), U.S.A, Louisiana (IMI 10032, type of Helminthosporium palmetto).
This species was illustrated by
On colonies of Irenopsis spp. and Meliola spp. on living leaves of various plants in Ghana, Malaysia, New Zealand, Puerto Rico, Sierra Leone and the U.S.A. (
Spiropes palmetto (IMI 10032) a conidiophore growing on a hypha of Meliola sp., shown in optical section b conidia shown in optical section. The thickness of the walls is only shown in the two last drawings c, d as seen by SEM c part of a conidiophore with a scar d conidium. Scale bars: 7 μm (a); 5 μm (b); 6 μm (c); 7 μm (d).
Spiropes palmetto can be easily recognised by the presence of conidia with two septa that delimit a barrel-shaped central cell and with a dark central pseudoseptum (
≡ Podosporium penicillium Speg., Boln. Acad. nac. Cienc. Córdoba 11: 618, 1889.
≡ Arthrobotryum penicillium (Speg.) F. Stevens, Bot. Gaz. 65: 238, 1918.
= Arthrobotryum strychni Henn., Hedwigia 43: 397, 1904.
≡ Podosporium strychni (Henn.) Cif., Sydowia 9: 311, 1955.
= Arthrobotryum glabroides F. Stevens, Bot. Gaz. 65: 237, 1918.
≡ Podosporium glabroides (F. Stevens) Cif., Sydowia 9: 309, 1955.
Colonies effuse, yellowish to dark olivaceous-brown, velvety, with tightly packed hyphae that form large, erect, dark synnemata clearly visible under the stereomicroscope. A bright yellow pigment diffuses out when colonies are mounted in lactic acid or lacto-phenol. Hyphae superficial, branched, septate, 1–2 µm wide, yellowish, pale olive, smooth. Conidiophores tightly packed to form dark brown to blackish synnemata up to 650 µm long, 10–40 µm thick, often splaying out to a width of 100 µm at the apex. Individual hyphae straight or flexuous, cylindrical, 1–2 µm thick near the base, 2–3.5 µm thick near the apex, pale olivaceous-brown, smooth, with numerous small conidial scars. Conidia solitary, fusiform or occasionally almost cylindrical, mostly 3(–5)–septate, 16–23(–37) × (3–)3.5–5(–7) µm, tapering to about 1 µm at the apex and base, middle cells pale brown, the cells at each end paler, surface wrinkled or verruculose. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks that can form ridges-like structures.
On Meliola calva on leaves of Lauraceae, Brasil, S. Paulo, Apiahy, 1881, J. Puiggari 1483 (IMI 131184, type of Podosporium penicillium); on Meliola sp. on leaves of Oxyanthus sp. (Rubiaceae), Sierra Leone, 1951, D.S. Rennis (IMI 51664).
This species was illustrated by
On colonies of Asteridiella spp. and Meliola spp. on living leaves of various plants in Brazil, Congo, Costa Rica, Ghana, Ivory Coast, Nigeria, Sierra Leone and Uganda (
Spiropes penicillium (IMI 51664) a conidiophores with scars (the thickness of the wall is shown on the right-handed drawing) b conidia shown in optical section (first two left-hand drawings) and as seen by SEM c, d as seen by SEM c tips of conidiophores with scars d conidia. Scale bars: 5 μm (a); 2.5 μm (b); 3 μm (c); 5 μm (d).
Spiropes penicillium is easily distinguishable from other known synnematous species of the genus Spiropes by the presence of fusiform to cylindrical conidia without rostra. In addition, a bright yellow pigment diffuses out of the cells when colonies are mounted in lactic acid or lacto-phenol (
1 | Conidiophores synnematous | 2 |
– | Conidiophores single or in groups | 7 |
2 | Synnemata straw-coloured to pale olivaceous; conidiophores with denticulate conidiogenous loci; pale multiseptate conidia | A. parasitica |
– | Synnemata dark brown to black; conidiophores with cicatrised conidiogenous loci; conidia pigmented and multiseptate | 3 |
3 | Synnemata up to 400 μm long; conidia mostly crescent shape | S. croissantiformis |
– | Synnemata longer, from 700 μm to 1.5 mm long; conidia fusiform to obclavate, occasionally cylindrical | 4 |
4 | Conidia fusiform to almost cylindrical; a yellow pigment diffuses out when colonies are mounted in lactic acid or lacto-phenol | S. penicillium |
– | Conidia fusiform to obclavate; no yellow pigment | 5 |
5 | Conidia always 4–6 septate | S. japonicus |
– | Conidia always 3–septate | 6 |
6 | Conidia 17–25 × 5–6.5 μm | S. clavatus |
– | Conidia 40–52 × 9–11 μm | S. melanoplaca |
7 | Conidia with 3–6 pseudosepta | 8 |
– | Conidia 1–3–septate | 10 |
8 | Conidiophores in larger groups; conidia with 3–6 (usually 4 or 5) pseudosepta | S. capensis |
– | Conidiophores single or in small groups; conidia with 3–5 pseudosepta | 9 |
9 | Conidiophores with zigzag shape; conidia with 3–5 pseudosepta, fusiform to obclavate | S. guareicola |
– | Conidiophores without zigzag shape; conidia with 3–4 pseudosepta, obovate | S. fumosus |
10 | Conidia 1–septate | 11 |
– | Conidia 3–septate | 12 |
11 | Conidia obpyriform, verrucose | S. armatellae |
– | Conidia obpyriform, smooth | S. armatellicola |
12 | Conidia oblong-ellipsoid | S. intricatus |
– | Conidia of various shapes, not oblong-ellipsoid | 13 |
13 | Conidia obovate to clavate; conidiophores swollen towards the apex or in areas where conidia are produced | S. deightonii |
– | Conidia ovate or fusiform to obclavate; conidiophores not swollen towards the apex or in areas where conidia are produced | 14 |
14 | Conidia obclavate; central cells barrel-shaped | 15 |
– | Conidia ovate or fusiform to obclavate; without central barrel-shaped cells | 16 |
15 | Conidia with 3 true septa | S. caribensis |
– | Conidia with 2 septa and a dark central pseudoseptum | S. palmetto |
16 | Conidia ovate | S. carpolobiae |
– | Conidia fusiform to obclavate | 17 |
17 | Conidia 3–4.5 μm wide | S. effusus |
– | Conidia wider | 18 |
18 | Conidia 17–25 μm long | S. angylocalycis |
– | Conidia longer | 19 |
19 | Conidia 20–35 μm long | S. dorycarpus |
– | Conidia longer | 20 |
20 | Conidia 36–48 μm long | S. helleri |
– | Conidia 40–54 μm long | S. leonensis |
In Fig.
In order to know the systematic positions of species of Atractilina and Spiropes hyperparasitic on Meliolales, new sequences of recently-collected specimens were obtained.
The BLAST query revealed that the nrLSU sequences of Atractilina parasitica (specimens MB136 and MB178) show approximately 82% similarity with sequences of species of the Dothideomycetes, such as Botryosphaeria spp., Helminthosporium asterinum Cooke, Hysterobrevium mori (Schwein.) E. Boehm & C.L. Schoch and Neoheleiosa lincangensis Mortimer, amongst others. In the tree inferred from the analysis of LSU sequences of 45 specimens of several orders of Dothideomycetes (Fig.
Phylogenetic tree inferred from a Maximum Likelihood analysis of nuc LSU rDNA sequences of members of the Dothideomycetes, including new sequences of Atractilina parasitica and Malacaria meliolicola (written with bold letters). The tree is rooted with sequences of species of the orders Capnodiales and Mycosphaerellales. Bootstrap values are indicated above the branches. Sequences downloaded from GenBank are given with accession numbers.
As for species of Spiropes, the BLAST query revealed that the nrITS sequences of Spiropes melanoplaca (specimens MB81 and MB119) and Spiropes japonicus (specimen MB 120) are not closely related to each other (60% similarity) and show between 88 and 90% similarity with species of the Leotiomycetes, such as Lophodermium actinothyrium Fuckel and Hypoderma spp., amongst others. Placement on to the Pezizomycotina tree version 2 in T-BAS confirmed that the newly-generated ITS sequences for the two species of Spiropes are placed in the Leotiomycetes (Fig.
Placement of Spiropes japonicus and S. melanoplaca on to Pezizomycotina reference tree version 2 in T-Bas. Only the Leotiomycetes clade is shown. The tree is the result of RAxML analysis of nuc ITS rDNA with 500 bootstraps replicates. For each node, the Maximum Likelihood bootstrap (≥ 70%) is presented as thick branches. Names of Spiropes species with newly-generated sequence data are written in bold.
Morphology-based identification of a species can be very difficult, especially amongst asexual or non-sporulating fungi (
The type species of Atractilina, Atractilina callicarpae Dearn. & Barthol. (= Atractilina parasitica (G. Winter) Deighton & Piroz.), has consistently true synnematous conidiophores, denticulate conidiogenous loci, pale pluriseptate (phragmoseptate) conidia and a hyperparasitic lifestyle (
The description of A. parasitica introduced by
The DNA molecular analyses of the nrLSU rDNA region of the specimens of A. parasitica from Benin revealed that this species belongs to the Dothideomycetes. The Dothideomycetes are the largest and most diverse class of fungi and comprise species that exhibit a broad range of lifestyles, including saprotrophs, plant pathogens, mycoparasites and hyperparasites, as well as lichenised and lichenicolous fungi (
As for the genus Spiropes, the generic diagnosis given by
Identifying species of Spiropes, based on morphology alone, is not always easy. The most comprehensive key to species of the genus was proposed by
As for the molecular-based identification of species of Spiropes, there are currently no DNA sequences available in publicly-accessible databases. Species of the genus remain “incertae sedis” for many taxonomic ranks and it is difficult to assign new DNA sequences to species concepts (
It is difficult to obtain molecular sequence data from hyperparasites especially because of the fact that they develop intermingled with the primary parasite and many other organisms and, as a result, no specific set of molecular methods has been developed to study hyperparasites (
Applications of names based on morphological characteristics without DNA data is a challenge, resulting in the description of an excessive number of species or, in contrast, in the overlooking of cryptic species that can only be detected through molecular analyses (
Atractilina and Spiropes are currently two repository genera of highly heterogeneous species and they may be split in the future, once species and genus concepts are validated respectively by morphology and molecular methods.
We are grateful to the University of Parakou and the University of Abomey-Calavi, Benin, for the support and facilities made available for this study. We acknowledge help by Dr. Pierre Agbani (Botanical Garden of the Université d’Abomey-Calavi) for his assistance with the identification of host plants and help by Daouda Dongnima during fieldwork. Special thanks to Affoussatou Tabé, Alicia Sanjur and Anna Krauss for their support and collecting efforts throughout the whole research process. We acknowledge the support and facilities made available by Orlando Cáceres and the Universidad Autónoma de Chiriquí (UNACHI) in Panama. The Environmental Ministry of Panama (MiAmbiente) is thanked for issuing the collection and export permits (SE/APHO-1-2019, SEX/H-5-2020, PA-01-ARG-049-2021). We are grateful to the Ministry of Environment of the Benin Republic for issuing the collecting permits and for the elaboration of the ABS Nagoya Protocol documents n° 636/DGEFC/ANC-APA/DCPRN/PF-APA.
The authors have declared that no competing interests exist.
No ethical statement was reported.
The first author acknowledges support from the German Academic Exchange Service (DAAD), within the framework of the scholarship programme for doctoral studies in Germany (Ref. no.: 91726217).
MB-C compiled and analyzed the data and wrote the first draft of the manuscript. MB-C, TH, NY and MP contributed to writing and editing the manuscript. All authors contributed to the article and approved the submitted version.
Miguel A. Bermúdez-Cova https://orcid.org/0000-0002-7712-7347
Tina A. Hofmann https://orcid.org/0000-0003-1124-402X
Nourou S. Yorou https://orcid.org/0000-0001-6997-811X
Meike Piepenbring https://orcid.org/0000-0002-7043-5769
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Alignments and tree generated during the analysis of the DNA sequences of Atractilina parasitica, Malacaria meliolicola and other members of the Dothideomycetes
Data type: docx
Explanation note: Alignment is shown in NEXUS format. The tree is shown in Newick format.