Research Article |
Corresponding author: Yu Pei Tan ( yupei.tan@daf.qld.gov.au ) Academic editor: Cecile Gueidan
© 2018 Yu Pei Tan, Pedro W. Crous, Roger G. Shivas.
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:
Tan YP, Crous PW, Shivas RG (2018) Cryptic species of Curvularia in the culture collection of the Queensland Plant Pathology Herbarium. MycoKeys 35: 1-25. https://doi.org/10.3897/mycokeys.35.25665
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Several unidentified specimens of Curvularia deposited in the Queensland Plant Pathology Herbarium were re-examined. Phylogenetic analyses based on sequence data of the internal transcribed spacer region, partial fragments of the glyceraldehyde-3-phosphate dehydrogenase and the translation elongation factor 1-α genes, supported the introduction of 13 novel Curvularia species. Eight of the species described, namely, C. beasleyi sp. nov., C. beerburrumensis sp. nov., C. eragrosticola sp. nov., C. kenpeggii sp. nov., C. mebaldsii sp. nov., C. petersonii sp. nov., C. platzii sp. nov. and C. warraberensis sp. nov., were isolated from grasses (Poaceae) exotic to Australia. Only two species, C. lamingtonensis sp. nov. and C. sporobolicola sp. nov., were described from native Australian grasses. Two species were described from hosts in other families, namely, C. coatesiae sp. nov. from Litchi chinensis (Sapindaceae) and C. colbranii sp. nov. from Crinum zeylanicum (Amaryllidaceae). Curvularia reesii sp. nov. was described from an isolate obtained from an air sample. Furthermore, DNA sequences from ex-type cultures supported the generic placement of C. neoindica and the transfer of Drechslera boeremae to Curvularia.
Dothideomycetes , multigene phylogeny, taxonomy, 13 new species
Curvularia is a species-rich genus of pathogens and saprobes associated with plant, human and animals worldwide (
Species delimitation within Curvularia based solely on morphology is difficult as many species share similar characters and have overlapping conidial dimensions. Currently, there are 131 species of Curvularia (excluding varieties) listed in Index Fungorum (accessed on 4 January 2018). Phylogenetic studies based on multilocus sequence analyses of ex-type or reference cultures have recently delimited many cryptic species (
In Australia, 64 species of Curvularia have been reported (
In this study, 17 unidentified isolates of Curvularia maintained in the culture collection held in the Queensland Plant Pathology Herbarium (BRIP) were compared with ex-type and reference isolates. Thirteen new species of Curvularia were revealed based on multilocus phylogenetic analyses and are formally described here. In addition, phylogenetic analyses of ex-type cultures have confirmed the placement of a Curvularia species, as well as the introduction of a new combination.
Unidentified isolates of Curvularia were obtained from BRIP (Table
Species | Isolate no.1 | Host | Location | GenBank accession numbers2 | ||
---|---|---|---|---|---|---|
ITS | gapdh | tef1a | ||||
Bipolaris maydis | CBS 136.29 T | Zea mays | USA | AF071325 | KM034846 | KM093794 |
Curvularia aeria | CBS 294.61 T | air | Brazil | HF934910 | HG779148 | – |
C. affinis | CBS 154.34 T | unknown | Indonesia | KJ909780 | KM230401 | KM196566 |
C. akaii | CBS 317.86 | unknown | Japan | KJ909782 | KM230402 | KM196569 |
C. akaiiensis | BRIP 16080 T | unknown | India | KJ415539 | KJ415407 | KJ415453 |
C. alcornii | MFLUCC 10-0703 T | Zea mays | Thailand | JX256420 | JX276433 | JX266589 |
C. americana | UTHSC 08-3414 T | Homo sapiens | USA | HE861833 | HF565488 | – |
C. asiatica | MFLUCC 10-0711 T | Panicum sp. | Thailand | JX256424 | JX276436 | JX266593 |
C. australiensis | BRIP 12044 T | Oryza sativa | Australia | KJ415540 | KJ415406 | KJ415452 |
C. australis | BRIP 12521 T | Sporobolus caroli | Australia | KJ415541 | KJ415405 | KJ415451 |
C. bannonii | BRIP 16732 T | Jacquemontia tamnifolia | USA | KJ415542 | KJ415404 | KJ415450 |
C. beasleyi sp. nov. | BRIP 10972 T | Chloris gayana | Australia | MH414892 | MH433638 | MH433654 |
BRIP 15854 | Leersia hexandra | Australia | MH414893 | MH433639 | MH433655 | |
C. beerburrumensis sp. nov. | BRIP 12942 T | Eragrostis bahiensis | Australia | MH414894 | MH433634 | MH433657 |
BRIP 12555 | Eragrostis sororia | Australia | MH414895 | MH433640 | MH433656 | |
C. boeremae comb. nov. | IMI 164633 T | Portulaca oleracea | India | MH414911 | MH433641 | – |
C. borreriae | MFLUCC 11-0422 | unknown Poaceae | Thailand | KP400638 | KP419987 | KM196571 |
C. bothriochloae | BRIP 12522 T | Bothriochloa bladhii | Australia | KJ415543 | KJ415403 | KJ415449 |
C. brachyspora | CBS 186.50 | Soil | India | KJ922372 | KM061784 | KM230405 |
C. buchloës | CBS 246.49 T | Buchloë dactyloides | USA | KJ909765 | KM061789 | KM196588 |
C. carica-papayae | CBS 135941 T | Carica papaya | India | HG778984 | HG779146 | – |
C. chiangmaiensis | CPC 28829 T | Zea mays | Thailand | MF490814 | MF490836 | MF490857 |
C. chlamydospora | UTHSC 07-2764 T | Homo sapiens | USA | HG779021 | HG779151 | – |
C. coatesiae sp. nov. | BRIP 24170 | air | Australia | MH414896 | MH433635 | MH433658 |
BRIP 24261 T | Litchi chinensis | Australia | MH414897 | MH433636 | MH433659 | |
C. clavata | BRIP 61680b | Oryza rufipogon | Australia | KU552205 | KU552167 | KU552159 |
C. coicis | CBS 192.29 T | Coix lacryma-jobi | Japan | AF081447 | AF081410 | JN601006 |
C. colbranii sp. nov. | BRIP 13066 T | Crinum zeylanicum | Australia | MH414898 | MH433642 | MH433660 |
C. crustacea | BRIP 13524 T | Sporobolus sp. | Indonesia | KJ415544 | KJ415402 | KJ415448 |
C. cymbopogonis | CBS 419.78 | Yucca sp. | Netherlands | HG778985 | HG779129 | – |
C. dactyloctenicola | CPC 28810 T | Dactyloctenium aegyptium | Thailand | MF490815 | MF490837 | MF490858 |
C. dactyloctenii | BRIP 12846 T | Dactyloctenium radulans | Australia | KJ415545 | KJ415401 | KJ415447 |
C. ellisii | CBS 193.62T | air | Pakistan | JN192375 | JN600963 | JN601007 |
C. eragrostidis | CBS 189.48 | Sorghum sp. | Indonesia | HG778986 | HG779154 | – |
C. eragrosticola sp. nov. | BRIP 12538 T | Eragrostis pilosa | Australia | MH414899 | MH433643 | MH433661 |
C. geniculata | CBS 187.50 | Andropogon sorghum | Indonesia | KJ909781 | KM083609 | KM230410 |
C. gladioli | CBS 210.79 | Gladiolus sp. | Romania | HG778987 | HG779123 | – |
C. graminicola | BRIP 23186 T | Aristida ingrata | Australia | JN192376 | JN600964 | JN601008 |
C. harveyi | BRIP 57412 T | Triticum aestivum | Australia | KJ415546 | KJ415400 | KJ415446 |
C. hawaiiensis | BRIP 11987 T | Oryza sativa | USA | KJ415547 | KJ415399 | KJ415445 |
C. heteropogonicola | BRIP 14579 T | Heteropogon contortus | India | KJ415548 | KJ415398 | KJ415444 |
C. heteropogonis | CBS 284.91 T | Heteropogon contortus | Australia | KJ415549 | JN600969 | JN601013 |
C. hominis | CBS 136985 T | Homo sapiens | USA | HG779011 | HG779106 | |
C. homomorpha | CBS 156.60 T | air | USA | JN192380 | JN600970 | JN601014 |
C. inaequalis | CBS 102.42 T | soil | France | KJ922375 | KM061787 | KM196574 |
C. intermedia | CBS 334.64 | Avena versicolor | USA | HG778991 | HG779155 | – |
C. ischaemi | CBS 630.82 T | Ischaemum indicum | Solomon Islands | JX256428 | JX276440 | – |
C. kenpeggii sp. nov. | BRIP 14530 T | Triticum aestivum | Australia | MH414900 | MH433644 | MH433662 |
C. kusanoi | CBS 137.29 | Eragrostis major | Japan | JN192381 | – | JN601016 |
C. lamingtonensis sp. nov. | BRIP 12259 T | Microlaena stipoides | Australia | MH414901 | MH433645 | MH433663 |
C. lunata | CBS 730.96 T | Homo sapiens | USA | JX256429 | JX276441 | JX266596 |
C. malina | CBS 131274 T | Zoysia matrella | USA | JF812154 | KP153179 | KR493095 |
C. mebaldsii sp. nov. | BRIP 12900 T | Cynodon transvaalensis | Australia | MH414902 | MH433647 | MH433664 |
BRIP 13983 | Cynodondactylon x transvaalensis | Australia | MH414903 | MH433646 | MH433665 | |
C. miyakei | CBS 197.29 T | Eragrostis pilosa | Japan | KJ909770 | KM083611 | KM196568 |
C. muehlenbeckiae | CBS 144.63 T | Sorghum sp. | USA | KP400647 | KP419996 | KM196578 |
C. neergaardii | BRIP 12919 T | Oryza sativa | Ghana | KJ415550 | KJ415397 | KJ415443 |
C. neoindica | IMI 129790 T | Brassica nigra | India | MH414910 | MH433649 | MH433667 |
C. nicotiae | BRIP 11983 T | soil | Algeria | KJ415551 | KJ415396 | KJ415442 |
C. nodosa | CPC 28800 T | Digitaria ciliaris | Thailand | MF490816 | MF490838 | MF490859 |
C. nodulosa | CBS 160.58 | Eleusine indica | USA | JN601033 | JN600975 | JN601019 |
C. oryzae | CBS 169.53 T | Oryza sativa | Vietnam | KP400650 | KP645344 | KM196590 |
C. ovariicola | CBS 470.90 T | Eragrostis interrupta | Australia | JN192384 | JN600976 | JN601020 |
C. pallescens | CBS 156.35 T | air | Indonesia | KJ922380 | KM083606 | KM196570 |
C. papendorfii | CBS 308.67 T | Acacia karroo | South Africa | KJ415552 | KJ415395 | KJ415441 |
C. petersonii sp. nov. | BRIP 14642 T | Dactyloctenium aegyptium | Australia | MH414905 | MH433667 | MH433668 |
C. perotidis | CBS 350.90 T | Perotis rara | Australia | JN192385 | KJ415394 | JN601021 |
C. pisi | CBS 190.48 T | Pisum sativum | Canada | KY905678 | KY905690 | KY905697 |
C. platzii sp. nov. | BRIP 27703b T | Cenchrus clandestinus | Australia | MH414906 | MH433651 | MH433669 |
C. portulacae | BRIP 14541 T | Portulaca oleracea | USA | KJ415553 | KJ415393 | KJ415440 |
C. prasadii | CBS 143.64 T | Jasminum sambac | India | KJ922373 | KM061785 | KM230408 |
C. protuberata | CBS 376.65 T | Deschampsia flexuosa | UK | KJ922376 | KM083605 | KM196576 |
C. pseudobrachyspora | CPC 28808 T | Eleusine indica | Thailand | MF490819 | MF490841 | MF490862 |
C. pseudolunata | UTHSC 09-2092 T | Homo sapiens | USA | HE861842 | HE861842 | – |
C. pseudorobusta | UTHSC 08-3458 | Homo sapiens | USA | HE861838 | HF565476 | – |
C. ravenelii | BRIP 13165 T | Sporobolus fertilis | Australia | JN192386 | JN600978 | JN601024 |
C. reesii sp. nov. | BRIP 4358 T | air | Australia | MH414907 | MH433637 | MH433670 |
C. richardiae | BRIP 4371 T | Richardia brasiliensis | Australia | KJ415555 | KJ415391 | KJ415438 |
C. robusta | CBS 624.68 T | Dichanthium annulatum | USA | KJ909783 | KM083613 | KM196577 |
C. ryleyi | BRIP 12554 T | Sporobolus creber | Australia | KJ415556 | KJ415390 | KJ415437 |
C. senegalensis | CBS 149.71 | unknown | Nigeria | HG779001 | HG779128 | – |
C. soli | CBS 222.96T | soil | Papua New Guinea | KY905679 | KY905691 | KY905698 |
C. sorghina | BRIP 15900 T | Sorghum bicolor | Australia | KJ415558 | KJ415388 | KJ415435 |
C. spicifera | CBS 274.52 | soil | Spain | JN192387 | JN600979 | JN601023 |
C. sporobolicola sp. nov. | BRIP 23040b T | Sporobolus australasicus | Australia | MH414908 | MH433652 | MH433671 |
C. subpapendorfii | CBS 656.74 T | soil | Egypt | KJ909777 | KM061791 | KM196585 |
C. trifolii | CBS 173.55 | Trifolium repens | USA | HG779023 | HG779124 | – |
C. tripogonis | BRIP 12375 T | Tripogon loliiformis | Australia | JN192388 | JN600980 | JN601025 |
C. tropicalis | BRIP 14834 T | Coffea arabica | India | KJ415559 | KJ415387 | KJ415434 |
C. tsudae | ATCC 44764 T | Chloris gayana | Japan | KC424596 | KC747745 | KC503940 |
C. tuberculata | CBS 146.63 T | Zea mays | India | JX256433 | JX276445 | JX266599 |
C. uncinata | CBS 221.52 T | Oryza sativa | Vietnam | HG779024 | HG779134 | – |
C. variabilis | CPC 28815 T | Chloris barbata | Thailand | MF490822 | MF490844 | MF490865 |
C. verruciformis | CBS 537.75 | Vanellus miles | New Zealand | HG779026 | HG779133 | – |
C. verruculosa | CBS 150.63 | Punica granatum | India | KP400652 | KP645346 | KP735695 |
C. warraberensis sp. nov. | BRIP 14817 T | Dactyloctenium aegyptium | Australia | MH414909 | MH433653 | MH433672 |
Curvularia sp. | BRIP 17068b | Micraira subulifolia | Australia | MH414904 | MH433648 | MH433666 |
BRIP 17439 | Trianthema portulacastrum | Australia | AF081449 | AF081406 | MH445455 |
Colonies were described from 7-d-old cultures grown on potato dextrose agar (PDA) (Becton Dickinson), incubated at room temperature (approx. 25 °C) and exposed to near-ultraviolet light on a diurnal cycle. Images of the colonies and herbarium specimens were captured by an Epson Perfection V700 scanner at a 300 dpi resolution. Colour of the colonies was rated according to
Isolates were grown on PDA for 7 d at room temperature (approx. 25 °C). Mycelium was scraped off the PDA cultures and macerated with 0.5 mm glass beads (Daintree Scientific) in a Tissue Lyser (Qiagen). Genomic DNA was extracted with the Gentra Puregene DNA Extraction Kit (Qiagen) according to the manufacturer’s instructions. Amplification and sequencing of the internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (gapdh) and the translation elongation factor 1-alpha (tef1α) loci followed the methods by
Unique fixed nucleotide positions were used to characterise and describe two cryptic species (see applicable species notes). For each of the cryptic species that was described, the closest phylogenetic neighbour was selected (Fig.
Phylogenetic tree based on maximum likelihood analysis of the combined multilocus alignment. RAxML bootstrap values (bs) greater than 70% and Bayesian posterior probabilities (pp) greater than 0.7 are given at the nodes (bs/pp). Novel species names are highlighted in blue. Ex-type isolates are marked with a T. The outgroup is Bipolaris maydis ex-type strain CBS 136.29.
Approximately 800 bp of the ITS region, 598 bp of the partial region of the gapdh gene and 969 bp of the partial region of the tef1α gene were sequenced from the BRIP isolates. After removing ambiguously aligned regions, the ITS, gapdh and tef1α alignments were trimmed to 474 bp, 544 bp and 867 bp, respectively. The ITS phylogeny was able to resolve 53 of 79 Curvularia species, including 10 of the new species (data not shown). The gapdh phylogeny inferred 12 new species and the tef1α phylogeny resolved all 13 of the new species (data not shown). As the topologies of the single locus phylogenies for the tree datasets did not show any conflicts, they were analysed in a concatenated alignment. The phylogenetic tree based on the concatenated alignment resolved the 17 BRIP isolates into 13 well-supported and unique clades (Fig.
Australia, Queensland, Beaudesert, from leaf spot on Chloris gayana, 9 Jan. 1974, J.L. Alcorn (holotype BRIP 10972, includes ex-type culture).
Colonies on PDA approx. 4 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous black. Hyphae subhyaline, smooth to branched, septate, up to 3 µm in width. Conidiophores branched, erect, straight to flexuous, geniculate towards apex, brown, paler towards apex, smooth, septate, up to 110 µm long, 4 µm wide; basal cell swollen and darker than the other cells, up to 6 µm diam. Conidiogenous cells integrated, terminal or intercalary, sympodial, pale brown, smooth, with darkened scars. Conidia fusiform, straight to slightly curved, rounded at the apex, (14–) 26–29 (–34) × (5–) 6.5–7.5 (–9) µm, brown to dark brown, 3–7 (mostly 5)-distoseptate; hila conspicuous, slightly protuberant, thickened and darkened, 1−1.5 µm wide.
Curvularia beasleyi (BRIP 10972): A colony on PDAB–C conidiophores and conidia D conidia. Curvularia beerburrumensis (BRIP 12942) E colony on PDAF chlamydospores G conidiophore H–I conidia. Curvularia boeremae (IMI 164633) J colony on PDAK conidiophores L conidia. Curvularia coatesiae (BRIP 24261) M colony on PDAN conidiophores O conidia. Scale bars: 1 cm (A, E, J, M); all others – 10 µm.
In recognition of Dr Dean R. Beasley, an Australian plant pathologist, for his dedication and numerous innovative contributions to the curation and promotion of the Queensland Plant Pathology Herbarium (BRIP).
Australia, Queensland, Atherton, from leaf spot on Leersia hexandra, 1 May 1987, J.L. Alcorn, BRIP 15854 (includes culture).
Curvularia beasleyi is placed in the same clade as C. dactyloctenii, C. hawaiiensis and C. nodosa (Fig.
Curvularia beasleyi is only known from Queensland on two unrelated grasses, the introduced host Chloris gayana and the native Leersia hexandra. There are many Curvularia species reported as associated with Chloris spp. (C. australiensis, C. australis, C. hawaiiensis, C. lunata, C. nodosa, C. pallescens, C. tsudae, C. variabilis, C. verruculosa) (
Australia, Queensland, Beerburrum, from blackened inflorescence of Eragrostis bahiensis, 24 May 1979, J.L. Alcorn (holotype BRIP 12942, includes ex-type culture).
Colonies on PDA approx. 2 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbrillate, olivaceous black. Hyphae subhyaline, smooth to asperulate, branched, septate, 3−4 µm in width; chlamydospores intercalary in chains, 4–9 µm, smooth, thick-walled. Conidiophores erect, straight to flexuous, geniculate towards apex, subhyaline to pale brown, smooth, septate, up to 500 µm long, 5−6 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia fusiform to subcylindrical or clavate, straight to slightly curved, rounded at the apex, (40–) 51–56 (–71) × (10–) 12–13 (–14) µm, subhyaline to pale yellowish-brown, 2–4 (mostly 3)-distoseptate; hila mostly inconspicuous or minutely thickened and darkened.
Named after the town Beerburrum, where the holotype was collected.
Australia, Queensland, Beerburrum, New South Wales, Yetman, blackened inflorescence of Eragrostis sororia, 12 May 1977, J.L. Alcorn, BRIP 12555 (includes culture).
Curvularia beerburrumensis is phylogenetically sister to C. australis and C. ovariicola (Fig.
Curvularia beerburrumensis is only known from inflorescences of the invasive South American grass Eragrostis bahiensis, as well as the Australian native E. sororia (
Drechslera boeremae A.S. Patil & V.G. Rao, Antonie van Leeuwenhoek 42: 129 (1976).
Colonies on PDA approx. 3 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous green to citrine, velutinous with aerial mycelium. Hyphae subhyaline, smooth to asperulate, branched, septate, 2–3 µm in width. Conidiophores straight to flexuous, slightly geniculate towards apex, uniformly subhyaline to pale brown, smooth, septate, up to 110 µm long, 4 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia broadly ellipsoidal to oval, brown to dark brown, smooth, (42–) 46–52 (–55) × (17–) 20–23 (–25) µm, brown to dark brown, 4–6-distoseptate, hila protuberant, thickened and darkened, 2–3 µm wide.
India, Poona, from leaves of Portulaca oleracea, 28 Apr. 1970, A.S. Patil (holotype IMI 164633, includes ex-type culture), (isotype BRIP 13934, includes ex-type culture).
Multilocus phylogenetic analyses placed the ex-type culture of D. boeremae within the clade that includes C. lunata, the type species of the genus (Fig.
Curvularia boeremae is only known from the type specimen on P. oleraceae and has not been recorded in Australia. Curvularia portulacae is the only other species recorded on P. oleraceae (
Australia, Queensland, Eudlo, from rotted fruit of Litchi chinensis, 28 Jan. 1992, L.M. Coates (holotype BRIP 24261, includes ex-type culture).
Colonies on PDA 6–7 cm diam. after 7 d at 25 °C, surface funiculose, floccose, olivaceous black at the centre, olivaceous to grey olivaceous towards the edge, margin fimbriate. Hyphae subhyaline, smooth to asperulate, septate, up to 3 µm in width. Conidiophores erect, flexuous, geniculate in the top half, uniformly brown, sometimes pale towards apex, septate, up to 190 µm long, 4 µm wide; basal cell sometimes swollen, up to 8 µm diam. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown, mono- or polytretic, with darkened nodes. Conidia ellipsoidal to obovoid, asymmetrical, sometimes the third cell from base is unequally enlarged, intermediate cells dark brown and usually verruculose, end cells paler and less ornamented than central cells, (20–) 23–26 (–30) × (7–) 8–9 (–10) µm, 3-distoseptate; hila protuberant, thickened and darkened, 1–2 µm wide.
Named after Dr Lindel (Lindy) M. Coates, an Australian plant pathologist in recognition of her contributions to the study of post-harvest fruit pathology.
Australia, New South Wales, Alstonville, isolated from the air in a mango orchard, 11 Mar. 1991, G.I. Johnson, BRIP 24170 (includes culture).
Curvularia coatesiae is morphologically similar and phylogenetically related to a reference culture of C. borreriae and the ex-type culture of C. pallescens (Fig.
Australia, Queensland, Brisbane, from leaf spot on Crinum zeylanicum, 11 Oct. 1976, R.C. Colbran (holotype BRIP 13066, includes ex-type culture).
Colonies on PDA approx. 5 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous black, aerial mycelium white. Hyphae subhyaline, smooth, septate, up to 3 µm in width. Conidiophores erect, flexuous, geniculate, uniformly pale brown to brown, smooth, septate, up to 145 µm long, 4–6 µm wide, basal cell sometimes swollen, up to 8 µm diam. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia fusiform to subcylindrical with rounded apex and obconical at the base, brown, end cells pale, (54–) 83–92 (–110) × (13–) 14–16 (–17) µm, brown to dark brown, 6–9-distoseptate; hila slightly protuberant, thickened and darkened, 1–2 µm wide.
Curvularia colbranii (BRIP 13066): A colony on PDAB conidiophore C–D conidia. Curvularia eragrosticola (BRIP 12538) E colony on PDAF conidiophore G chlamydosphores H conidia. Curvularia kenpeggii (BRIP 14530) I colony on PDAJ conidiophores and conidium K conidia. Curvularia lamingtonensis (BRIP 12259) L colony on PDAM conidiophore O conidia. Scale bars: 1 cm (A, E, I, L); all others – 10 µm.
Named after Dr Robert (Bob) Chester Colbran (1926–2010), an Australian nematologist and Director of the Plant Pathology Branch, Queensland Department of Primary Industries, in recognition of his significant contributions to Australian plant pathology.
Curvularia colbranii is sister to C. boeremae, C. lamingtonensis (see this paper), C. neoindica and C. portulacae, although separated by a considerable genetic distance (Fig.
Only one other species, C. trifolii, has been reported on Crinum sp. (
Australia, New South Wales, Yetman, from inflorescence on Eragrostis pilosa, 12 May 1977, J.L. Alcorn (holotype BRIP 12538, includes ex-type culture).
Colonies on PDA approx. 2 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, dark olive with white patches, velutinous with some aerial mycelium. Hyphae subhyaline, smooth, branched, septate, 4−5 µm wide; chlamydospores abundant, subglobose to ellipsoidal or irregular, terminal and intercalary, 5−20 µm diam. Conidiophores erect, straight to flexuous, slightly geniculate, pale brown to brown, paler towards apex smooth, septate, up to 145 µm long, 4−5 µm wide. Conidiogenous cells integrated, terminal or intercalary, sympodial, pale brown to brown, smooth, with darkened scars. Conidia hemi-ellipsoidal, curved, asymmetrical, brown to dark brown, end cells slightly paler, (25–) 26–30 (–34) × (9–) 13–15 (–19) µm, 3-distoseptate with a faint narrow median septum; hila non-protuberant, minutely thickened and darkened.
Named after Eragrostis, the grass genus from which this fungus was isolated.
Curvularia eragrosticola is phylogenetically close to C. papendorfii and C. sporobolicola (see this paper) (Fig.
Curvularia eragrosticola is only known from the type specimen on Eragrostis pilosa, which is native to Eurasia and Africa and is considered a troublesome weed in Australia (
Australia, Queensland, from mouldy grain of Triticum aestivum, 26 Oct. 1984, J.L. Alcorn (holotype BRIP 14530, includes ex-type culture), (isotype IMI 290719).
Colonies on PDA 3–4 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, floccose and olivaceous black at the centre with white patches, velutinous with some aerial mycelium. Hyphae hyaline, asperulate, branched, septate, 4−5 µm in width. Conidiophores erect, straight to flexuous, slightly geniculate in the upper part, pale brown to brown, sometimes paler towards the apex, verrucose, septate, up to 360 µm long, 4−5 µm wide, basal cell sometimes swollen, up to 8 µm. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia ellipsoidal to clavate to obovoid, asymmetrical, third cell from the base is unequally enlarged, brown, end cells paler, verruculose, (31–) 35–39 (–42) × (10–) 13–14 (–15) µm, 3-distoseptate, hila protuberant, thickened and darkened, 1–2 µm wide.
Named after Dr Kenneth G. Pegg AM (member of the Order of Australia), in celebration of his 60 years of dedication to plant pathology in Australia and to thank him for his generous mentorship.
Curvularia kenpeggii is only known from the holotype specimen and is genetically distinct from all other Curvularia species (Fig.
Australia, Queensland, Lamington National Park, from Microlaena stipoides, 09 May 1977, J.L. Alcorn (holotype BRIP 12259, includes ex-type culture).
Colonies on PDA cover the whole plate after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous green, velutinous with some aerial mycelium. Hyphae hyaline, branched, septate, 4 µm in width. Conidiophores erect, straight to flexuous, geniculate towards apex, pale brown to dark brown on wheat straw agar, septate, up to 160 µm long, 3−4 µm wide. Conidiogenous cells integrated, terminal or intercalary, sympodial, pale brown to brown, smooth, with darkened scars. Conidia ellipsoidal to fusiform, straight, pale brown, (45–) 59–66 (–76) × (11–) 11.5–13 (–14) µm, 4–11-distoseptate with inconspicuous transverse septa, hila protuberant, thickened and darkened, 1–2 µm wide.
Named after the locality, Lamington National Park, where the holotype was collected.
Curvularia lamingtonensis is phylogenetically closely related to C. boeremae and C. neoindica. Curvularia lamingtonensis is distinguished from the ex-type culture of C. boeremae in two loci (96% in ITS and 98% in gapdh) and from the ex-type culture of C. neoindica in three loci (95% in ITS, 98% in gapdh and 99% in tef1α). Curvularia lamingtonensis has longer and straighter conidia than C. boeremae and C. neoindica, both of which have broad, ellipsoidal conidia (42–55 × 20–23 µm, and 27–65 × 17–27 µm, respectively). Curvularia lamingtonensis is only known from the type specimen on Microlaena stipoides. This is the first record of a Curvularia species associated with Microlaena.
Australia, Victoria, Hopetoun, from Cynodon transvaalensis, Apr. 1979, M. Mebalds (holotype BRIP 12900, includes ex-type culture).
Colonies on PDA approx. 5 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous black with white patches, velutinous with some aerial mycelium. Hyphae hyaline to subhyaline, smooth to asperulate, septate, 3–4 µm wide. Conidiophores erect, straight to flexuous, sometimes slightly geniculate towards apex, branched, uniformly brown, paler at apex, smooth to asperulate, septate, up to 180 µm long, 4–5 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, subhyaline to pale brown, smooth, mono- or polytretic, with darkened scars. Conidia ellipsoidal to obovoid, sometimes straight to slightly curved, rounded at the apex, (22–) 25–28 (–30) × (7–) 8–9 (–10) µm, pale brown to brown, 3-distoseptate, hila protuberant, thickened and darkened, 1–2 µm wide.
Curvularia mebaldsii (BRIP 12900): A colony on PDAB conidiophores and conidium C conidia. Curvularia petersonii (BRIP 14642) D colony on PDAE–F conidiophores and conidium G conidia. Curvularia platzii (BRIP 27703b) H colony on PDAI conidiophores J–K conidia. Scale bars: 1 cm (A, D, H); all others – 10 µm.
Named after the collector, Martin Mebalds, in recognition of his contributions to Australian plant pathology and biosecurity.
Australia, New South Wales, Tweed Heads, from necrotic leaf on Cynodon dactylon × transvaalensis, 10 Jun. 1983, G. Thomas, BRIP 13983 (includes culture).
The multilocus phylogenetic analyses showed that C. mebaldsii was sister to C. tsudae, although separated by a considerable genetic distance (Fig.
Curvularia mebaldsii is known from two specimens on Cynodon spp. Several Curvularia species have been associated with Cynodon, including C. aeria, C. australiensis, C. brachyspora, C. clavata, C. fallax, C. geniculata, C. hawaiiensis, C. inaequalis, C. lunata, C. pallescens, C. ramosa, C. senegalensis, C. spicata, C. spicifera and C. verruculosa (
Australia, Northern Territory, Daly Waters, from leaf spot on Dactyloctenium aegyptium, 20 Mar. 1985, R.A. Peterson (holotype BRIP 14642, includes ex-type culture).
Colonies on PDA approx. 5 cm diam. after 7 d at 25 °C, surface funiculose, olivaceous black, velutinous with some aerial mycelium, margin fimbriate. Hyphae subhyaline, smooth to asperulate, septate, up to 3 µm in width. Conidiophores erect, straight to flexuous, rarely branched, slightly geniculate, uniformly brown, sometimes pale brown at apex, smooth, septate, up to 110 µm long, 4 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia obovoid to ellipsoidal, straight to slightly curved, (15–) 17–19 (–21) × (5–) 5.5–6 (–7) µm, brown, end cells pale, 3-distoseptate, hila non-protuberant, thickened and darkened.
Named after Ron A. Peterson, an Australian plant pathologist, in recognition of his contributions to tropical plant pathology.
The multilocus phylogenetic analyses placed C. petersonii sister to C. americana and C. verruculosa, although separated by a considerable genetic distance (Fig.
Curvularia petersonii is only known from a single specimen on Dactyloctenium aegyptium in the Northern Territory. Many Curvularia species have been associated with Dactyloctenium, including C. clavata, C. dactyloctenicola, C. dactyloctenii, C. eragrostidis, C. lunata, C. neergaardii, C. pallescens and C. verruculosa (
Australia, Queensland, Warwick, from leaf spot on Cenchrus clandestinus, 24 Jan. 2001, G.J. Platz (holotype BRIP 27703b, includes ex-type culture).
Colonies on PDA approx. 2 cm diam. after 7 d at 25 °C, surface dark olivaceous green. Hyphae subhyaline, smooth, septate, up to 3 µm wide. Conidiophores erect, straight to flexuous, geniculate towards apex, uniformly brown, sometimes pale brown towards apex, septate, up to 75 µm long, 5–6 µm wide, swollen at base, 8–10 µm. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia fusiform to narrowly clavate, brown, end cells sometimes paler, (65–) 94–105 (–115) × (11–) 12.5–13.5 (–14) µm, 9–13-distoseptate; hila non-protuberant, thickened and darkened.
Named after Gregory (Greg) J. Platz, in recognition of his contributions to Australian cereal plant pathology for the past 30 years, as well as his prowess as an international and Queensland rugby league footballer.
The multilocus phylogenetic analyses indicated C. platzii was sister to C. hominis, C. meuhlenbeckiae and C. pisi (Fig.
Curvularia platzii is only known from the holotype. The host, Cenchrus clandestinus (syn. Pennisetum clandestinus), is a perennial grass with a worldwide distribution (
Australia, Queensland, Brisbane, isolated from air, 22 Jun. 1963, R.G. Rees (holotype BRIP 4358, includes ex-type culture).
Colonies on PDA approx. 6−7 cm diam. after 7 d at 25 °C, surface funiculose, greenish-grey, velutinous with some aerial mycelium, margin fimbriate. Hyphae hyaline, branched, septate, 3−4 µm in width. Conidiophores erect, straight to flexuous, slightly geniculate towards apex, pale brown to brown, sometimes paler towards the apex, septate, up to 200 µm long, 4−5 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia ellipsoidal to obclavate, straight, third cell from pore swollen, brown, end cells paler, smooth, (28–) 31–35 (–39) × (10–) 12–13 (–14) µm, mostly 3 septate; hila inconspicuous, sometimes darkened.
Named after Dr Robert (Bob) G. Rees, an Australian plant pathologist, in recognition of his extensive contributions to cereal pathology.
The multilocus phylogenetic analyses indicated C. reesii was sister to C. oryzae and C. tuberculata. Curvularia reesii is distinguished in two loci from the ex-type cultures of C. oryzae (98% in gapdh and 99% in tef1α) and C. tuberculata (96% in gapdh and 99% in tef1α). Morphologically, C. reesii has conidia similar in size to C. oryzae (24–40 × 12–22 µm,
Australia, Queensland, Musselbrook Reserve, leaf of Sporobolus australasicus, 2 May 1995, J.L. Alcorn (holotype BRIP 23040b, includes ex-type culture).
Colonies on PDA approx. 6 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous black, velutinous. Hyphae subhyaline, smooth, branched, septate, 3 µm wide. Conidiophores erect, straight to flexuous, geniculate, pale yellowish-brown, septate, up to 55 µm long, 4−5 µm wide, basal cell swollen, 6−10 µm diam. Conidiogenous cells cylindrical, slightly flared at the apex, integrated, sympodial, pale brown, smooth, with darkened and thickened scars. Conidia hemi-ellipsoidal, curved, 4-distoseptate with a faint narrow median septum, (34–) 37–41 (–45) × (14–) 17–20 (–23) µm, brown to dark brown, end cells rounded and paler, hila non-protuberant, sometimes darkened.
Named after Sporobolus, the grass genus from which it was isolated.
Based on multilocus phylogenetic analyses, C. sporobolicola clustered sister to C. papendorfii, which are both sister to C. eragrosticola (Fig.
Curvularia sporobolicola is only known from the type specimen on S. australasicus, which is a native Australian grass with a broad distribution in the tropics and subtropics (
Australia, Queensland, Torres Strait, Warraber Island, from leaf spot on Dactyloctenium aegyptium, 2 Jun. 1985, R.A. Peterson (holotype BRIP 14817, includes ex-type culture).
Colonies on PDA 6–7 mm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous green, velutinous with some aerial mycelium. Hyphae subhyaline, smooth, septate, up to 3 µm wide. Conidiophores erect, flexuous, geniculate towards apex, uniformly pale brown to brown, septate, up to 360 µm long, 4–5 µm wide, basal cell sometimes swollen, 6–8 µm diam. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia ellipsoidal, curved, the third cell from base swollen, end cells paler, smooth, (20–) 23–26 (–28) × (8–) 9.5–11 µm, pale brown to brown, 3-distoseptate, hila conspicuous, sometimes slightly protuberant, thickened and darkened.
Named after the locality, Warraber Island in the Torres Straits, where the specimen was collected.
Multilocus phylogenetic analyses placed C. warraberensis sister to C. caricae-papayae and C. prasadii (Fig.
Curvularia warraberensis is only known from the holotype. Curvularia species associated with Dactyloctenium are listed in the notes for C. petersonii.
Although the ITS locus is the universal barcode marker for fungi (
Eight Curvularia species are described here from grasses (Poaceae) exotic to Australia, namely, C. beasleyi on Chloris gayana, C. beerburrumensis on Eragrostis bahiensis, C. eragrosticola on E. pilosa, C. kenpeggii on Triticum aestivum, C. mebaldsii on Cynodondactylon × transvaalensis, C. petersonii and C. warraberensis on Dactyloctenium aegyptium and C. platzii on Cenchrus clandestinus. Only two species were described from native Australian grasses, C. lamingtonensis on Microlaena stipoides and C. sporobolicola on Sporobolus australasicus. Two species were described from other hosts, C. coatesiae from Litchi chinensis (Sapindaceae) and C. colbranii from Crinum zeylanicum (Amaryllidaceae). One species, C. reesii, was described from an isolate obtained from an air sample. Furthermore, DNA sequences derived from ex-type cultures have supported the generic placement of C. neoindica and the transfer of Drechslera boeremae to Curvularia.
It is not known whether the species described here are pathogens, endophytes or saprobes. It is also unclear as to whether these species are native or introduced. Curvularia beasleyi and C. beerburrumensis were both isolated from a native Australian grass species, as well as an exotic host. Some grass species have been reported to be associated with multiple Curvularia species, such as Chloris and Cynodon, with nine and 15 species, respectively. Many of the published records on Chloris and Cynodon have not been verified by molecular analyses. The number of new species described from non-Australian grasses indicates a need for a molecular-based reassessment of previous host-species records. The description of these species provides a foundation upon which additional sampling and accumulation of molecular data will improve knowledge of the host ranges and ecological roles of helminthosporioid fungi in Australia and overseas.
The authors wish to thank Dr John L. Alcorn (former curator of the BRIP) for his support, as well as acknowledge his foresight in preserving the cultures examined in this study.