Curvularia

Boedijn Bull. Jard. Bot. Buitenzorg, 3 Sér. 13: 123. 1933.

Synonyms: Malustela Bat. & J.A. Lima, Publ. Inst. Micol. Recife 263: 5. 1960.
Curvusporium Corbetta as “Curvosporium”, Riso 12: 28, 30. 1963.
Pseudocochliobolus Tsuda, et al., Mycologia 69: 1117. 1978.
Classification: Dothideomycetes, Pleosporomycetidae, Pleosporales, Pleosporaceae
Type species: Curvularia lunata (Wakker) Boedijn. Ex-neotype culture: CBS 730.96
DNA barcodes (genus): LSU, ITS.
DNA barcodes (species): ITS, gapdh, tef1.

Ascomata pseudothecial, mostly globose to ellipsoidal, sometimes flask-shaped or flattened on hard substrata, brown or black, immersed, erumpent, partially embedded or superficial, free or developing on a basal columnar or flat stroma, smooth or covered with vegetative filaments; ostiole central, papillate or with a sub-conical, conical, paraboloid or cylindrical neck; ascomatal wall comprising pseudoparenchymatous cells of equal thickness or slightly thickened at apex of the ascoma. Hamathecium comprising septate, filiform, branched pseudoparaphyses. Asci bitunicate, clavate, cylindrical-clavate or broadly fusoid, straight or slightly curved, thin-walled, fissitunicate, often becoming more or less distended prior to dehiscence, short pedicellate, rounded at the apex. Ascospores multiseriate, filiform or flagelliform, hyaline or sometimes pale yellow or pale brown at maturity, septate, helically coiled within ascus, degree of ascospore coiling moderate to very strongly coiled, often with a mucilaginous sheath. Conidiophores straight to flexuous, often geniculate, multiseptate, usually simple, sometimes branched, smooth to verruculose, macronematous, mononematous, sometimes nodose, cylindrical. Conidiogenous nodes cylindrical, integrated, terminal and intercalary, proliferating sympodially, cicatrized. Conidia solitary, often curved, acropleurogenous, broadly fusoid, elliptical, obovoid or obpyriform, mostly smooth, sometimes verruculose, echinulate or tuberculate, 3 or more distoseptate, with or without an unequally swollen cell which is more pigmented than the other cells, septa sometimes accentuated with a dark band in some or all the cells, germinating mainly from one or both polar cells with the basal germ tube growing semiaxially, hilum in a slightly protruding truncate basal section of the conidial wall and often visible as two dark lenticular spots in optical section arranged close together with a small obscure narrow separating canal between them or distinctly protuberant, first conidial septum median or submedian, second septum often delimiting the basal cell of the mature conidium, third septum then distal. Microconidiation not common, producing conidia 1–2-celled, pale brown, globose to subglobose (adapted from Sivanesan 1987).

Culture characteristics:

Colonies on PDA white or pale grey when young, orange to brown or different shades of grey (mainly dark olivaceous grey) when mature, fluffy, cottony, raised or convex with papillate surface, margin lobate, undulate, entire or sometimes rhizoid.

Optimal media and cultivation conditions: Sterilised Zea mays leaves placed on 1.5 % WA or slide cultures of half-strength PDA under near-ultraviolet light (12 h light, 12 h dark) to induce sporulation of the asexual morph, while for the sexual morph Sach's agar with sterilised rice or wheat straw at 25 °C is used.

Distribution:

Worldwide.

Hosts:

Wide host range, occurring as pathogens, saprobes or endophytes. Mainly found on members of the Poaceae, being pathogens of grass and staple crops, including rice, maize, wheat and sorghum. This genus also occurs on genera belonging to Actinidiaceae, Aizoaceae, Caricaceae, Convolvulaceae, Fabaceae, Iridaceae, Lamiaceae, Lythraceae, Oleaceae, Polygonaceae and Rubiaceae.

Disease symptoms:

Leaf spots, leaf blight, melting out, root rot, foot rot, among others.

Notes:

Species delimitation in Curvularia based on morphology only is difficult due to the morphological complexity within this genus, as also observed in Bipolaris. Furthermore, the distinction of both genera based on morphology alone is sometimes complicated (see Bipolaris notes for morphological differences between Bipolaris and Curvularia). Therefore, molecular data are essential for an accurate identification of species within these genera, ITS, gapdh and tef1 being the loci selected for this purpose (Manamgoda et al. 2014, 2015).

Curvularia is a rich genus in host range and geographic distribution compared to Bipolaris. Apart from phytopathogenic species, this genus comprises species that are pathogens of humans and other animals, causing respiratory tract, cutaneous, cerebral and corneal infections, mainly in immunocompromised patients (Carter & Boudreaux 2004). Some species can be found in association with both humans and plants, such as Cu. hawaiiensis, Cu. lunata and Cu. spicifera (Manamgoda et al. 2015).

References:

Sivanesan 1987 (morphology and pathogenicity); Manamgoda et al. 2011 (pathogenicity), Manamgoda et al. 2015 (morphology, pathogenicity and phylogeny).
Carter E, Boudreaux C (2004). Fatal cerebral phaeohyphomycosis due to Curvularia lunata in an immunocompetent patient. Journal of Clinical Microbiology 42: 5419–5423.
Manamgoda DS, Cai L, Bahkali AH, et al. (2011). Cochliobolus: an overview and current status of species. Fungal Diversity 51: 3–42.
Manamgoda DS, Rossman AY, Castlebury LA, et al. (2014). The genus Bipolaris. Studies in Mycology 79: 221–288.
Manamgoda DS, Rossman AY, Castlebury LA, et al. (2015). A taxonomic and phylogenetic re-appraisal of the genus Curvularia (Pleosporaceae): human and plant pathogens. Phytotaxa 212: 175–198.
Sivanesan A (1987). Graminicolous species of Bipolaris, Curvularia, Drechslera, Exserohilum and their teleomorphs. Mycological Papers 158: 1–261.

Table 9. DNA barcodes of accepted Curvularia spp.

Species	Isolates¹		GenBank accession numbers²			References
		ITS		*gapdh*	*tef1*
Cu. aeria	CBS 294.61^T	HE861850		HF565450	-	da Cunha et al. (2013)
Cu. affinis	CBS 154.34^SynT	KJ909780		KM230401	KM196566	Manamgoda et al. (2015)
Cu. akaii	CBS 317.86	KJ909782		KM230402	KM196569	Manamgoda et al. (2015)
Cu. akaiiensis	BRIP 16080^IsoT	KJ415539		KJ415407	KJ415453	Tan et al. (2014)
Cu. alcornii	MFLUCC 10-0703^T	JX256420		JX276433	JX266589	Manamgoda et al. (2012a)
Cu. americana	UTHSC 08-3414^T	HE861833		HF565488	-	Madrid et al. (2014)
Cu. asiatica	MFLUCC 10-0711^T	JX256424		JX276436	JX266593	Manamgoda et al. (2012a)
Cu. australiensis	BRIP 12044^T	KJ415540		KJ415406	KJ415452	Tan et al. (2014)
Cu. australis	BRIP 12521^T	KJ415541		KJ415405	KJ415451	Tan et al. (2014)
Cu. bannonii	BRIP 16732^IsoT	KJ415542		KJ415404	KJ415450	Tan et al. (2014)
Cu. borreriae	CBS 859.73	HE861848		HF565455	-	da Cunha et al. (2013)
Cu. bothriochloae	BRIP 12522^T	KJ415543		KJ415403	KJ415449	Tan et al. (2014)
Cu. brachyspora	CBS 186.50	KJ922372		KM061784	KM230405	Manamgoda et al. (2014)
Cu. buchloës	CBS 246.49^T	KJ909765		KM061789	KM196588	Manamgoda et al. (2014)
Cu. carica-papayae	CBS 135941^T	HG778984		HG779146	-	Madrid et al. (2014)
Cu. chlamydospora	UTHSC 07-2764^T	HG779021		HG779151	-	Madrid et al. (2014)
Cu. clavata	BRIP 61680b	KU552205		KU552167	KU552159	Khemmuk et al. (2016)
Cu. coicis	CBS 192.29^SynT	JN192373		JN600962	JN601006	Manamgoda et al. (2015)
Cu. crustacea	BRIP 13524^ET	KJ415544		KJ415402	KJ415448	Tan et al. (2014)
Cu. cymbopogonis	CBS 419.78	HG778985		HG779129	HG779163	Madrid et al. (2014)
Cu. dactyloctenii	BRIP 12846^T	KJ415545		KJ415401	KJ415447	Tan et al. (2014)
Cu. ellisii	CBS 193.62^T	JN192375		JN600963	JN601007	Manamgoda et al. (2011)
Cu. eragrostidis	CBS 189.48	HG778986		HG779154	HG779164	Madrid et al. (2014)
Cu. geniculata	CBS 187.50	KJ909781		KM083609	KM230410	Manamgoda et al. (2015)
Cu. gladioli	CBS 210.79	HG778987		HG779123	-	Madrid et al. (2014)
Cu. graminicola	BRIP 23186^T	JN192376		JN600964	JN601008	Manamgoda et al. (2012b)
Cu. gudauskasii	DAOM 165085	AF071338		-	-	Berbee et al. (1999)
Cu. harveyi	BRIP 57412^IsoT	KJ415546		KJ415400	KJ415446	Tan et al. (2014)
Cu. hawaiiensis	BRIP 11987^IsoLT	KJ415547		KJ415399	KJ415445	Tan et al. (2014)
Cu. heteropogonicola	BRIP 14579^IsoT	KJ415548		KJ415398	KJ415444	Tan et al. (2014)
Cu. heteropogonis	CBS 284.91^T	JN192379		JN600969	JN601013	Manamgoda et al. (2012b)
Cu. hominis	CBS 136985^T	HG779011		HG779106	-	Madrid et al. (2014)
Cu. homomorpha	CBS 156.60^T	JN192380		JN600970	JN601014	Manamgoda et al. (2014)
Cu. inaequalis	CBS 102.42^T	KJ922375		KM061787	KM196574	Manamgoda et al. (2014)
Cu. intermedia	CBS 334.64	HG778991		HG779155	HG779169	Madrid et al. (2014)
Cu. ischaemi	CBS 630.82^T	JX256428		JX276440	-	Manamgoda et al. (2012b)
Cu. kusanoi	CBS 137.29	JN192381		-	JN601016	Manamgoda et al. (2015)
Cu. lunata	CBS 730.96^NT	JX256429		JX276441	JX266596	Manamgoda et al. (2012b)
Cu. malina	CBS 131274^T	JF812154		KP153179	KR493095	Tomaso-Peterson et al. (2016)
Cu. miyakei	CBS 197.29^SynT	KJ909770		KM083611	KM196568	Manamgoda et al. (2014)
Cu. muehlenbeckiae	CBS 144.63^T	HG779002		HG779108	-	Madrid et al. (2014)
Cu. neergaardii	BRIP 12919^IsoT	KJ415550		KJ415397	KJ415443	Tan et al. (2014)
Cu. neoindica	BRIP 17439	AF081449		AF081406	-	Berbee et al. (1999)
Cu. nicotiae	CBS 655.74^IsoT = BRIP 11983	KJ415551		KJ415396	KJ415442	Tan et al. (2014)
Cu. nodulosa	CBS 160.58	JN601033		JN600975	JN601019	Manamgoda et al. (2015)
Cu. oryzae	CBS 169.53^IsoT	KP400650		KP645344	KM196590	Manamgoda et al. (2015)
Cu. ovariicola	CBS 470.90^T	JN192384		JN600976	JN601020	Manamgoda et al. (2012b)
Cu. papendorfii	CBS 308.67^T	KJ909774		KM083617	KM196594	Manamgoda et al. (2014)
Cu. pallescens	CBS 156.35^T	KJ922380		KM083606	KM196570	Manamgoda et al. (2015)
Cu. perotidis	CBS 350.90^T	JN192385		KJ415394	JN601021	Manamgoda et al. (2015)
Cu. pisi	CBS 190.48^T	KY905678		KY905690	KY905697	Marin-Felix et al. (2017)
Cu. portulacae	CBS 239.48^IsoT=	KJ909775		KM083616	-	Manamgoda et al. (2014)
	BRIP 14541^IsoT	KJ415553		KJ415393	KJ415440	Tan et al. (2014)
Cu. prasadii	CBS 143.64^T	KJ922373		KM061785	KM230408	Manamgoda et al. (2014)
Cu. protuberata	CBS 376.65^IsoT	KJ922376		KM083605	KM196576	Manamgoda et al. (2014)
Cu. pseudolunata	UTHSC 09-2092^T	HE861842		HF565459	-	da Cunha et al. (2013)
Cu. pseudorobusta	UTHSC 08-3458	HE861838		HF565476	-	da Cunha et al. (2013)
Cu. ravenelii	BRIP 13165^T	JN192386		JN600978	JN601024	Manamgoda et al. (2012b)
Cu. richardiae	BRIP 4371^IsoLT	KJ415555		KJ415391	KJ415438	Tan et al. (2014)
Cu. robusta	CBS 624.68^IsoT	KJ909783		KM083613	KM196577	Manamgoda et al. (2014)
Cu. ryleyi	BRIP 12554^T	KJ415556		KJ415390	KJ415437	Tan et al. (2014)
Cu. senegalensis	CBS 149.71	HG779001		HG779128	-	Madrid et al. (2014)
Cu. sesuvi	Bp-Zj 01	EF175940		-	-	Zhang & Li (2009)
Cu. soli	CBS 222.96^T	KY905679		KY905691	KY905698	Marin-Felix et al. (2017)
Cu. sorghina	BRIP 15900^IsoT	KJ415558		KJ415388	KJ415435	Tan et al. (2014)
Cu. spicifera	CBS 274.52	JN192387		JN600979	JN601023	Manamgoda et al. (2012b)
Cu. subpapendorfii	CBS 656.74^T	KJ909777		KM061791	KM196585	Manamgoda et al. (2015)
Cu. trifolii	CBS 173.55	HG779023		HG779124	-	Madrid et al. (2014)
Cu. tripogonis	BRIP 12375^T	JN192388		JN600980	JN601025	Manamgoda et al. (2011)
Cu. tropicalis	BRIP 14834^IsoT	KJ415559		KJ415387	KJ415434	Tan et al. (2014)
Cu. tsudae	ATCC 44764^PT	KC424596		KC747745	KC503940	Deng et al. (2014)
Cu. tuberculata	CBS 146.63^IsoT	JX256433		JX276445	JX266599	Manamgoda et al. (2012b)
Cu. uncinata	CBS 221.52^T	HG779024		HG779134	-	Madrid et al. (2014)
Cu. verruciformis	CBS 537.75	HG779026		HG779133	HG779211	Madrid et al. (2014)
Cu. verruculosa	CBS 150.63	KP400652		KP645346	KP735695	Manamgoda et al. (2015)

¹ATCC: American Type Culture Collection, Virginia, USA; BRIP: Queensland Plant Pathology Herbarium, Brisbane, Australia; Bp-Zj: Isolate housed in Biotechnology Institute, Zhejiang University, Hangzhou, China; CBS: Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands; DAOM: Plant Research Institute, Department of Agriculture (Mycology), Ottawa, Canada; MFLUCC: Mae Fah Luang University Culture Collection, Chiang Ria, Thailand, UTHSC: Fungus Testing Laboratory, Department of Pathology at the University of Texas Health Science Center, San Antonio, Texas, USA. ^{ET and IsoT, IsoLT, PT, SynT, T}indicate ex-epitype, ex-isotype, ex-isolectotype, ex-paratype, ex-syntype and ex-type strains, respectively.

²ITS: internal transcribed spacers and intervening 5.8S nrDNA; gapdh: partial glyceraldehyde-3-phosphate dehydrogenase gene; tef1: partial translation elongation factor 1-alpha gene.

Berbee ML, Pirseyedi M, Hubbard S (1999). Cochliobolus phylogenetics and the origin of known, highly virulent pathogens, inferred from ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences. Mycologia 91: 964–977.
da Cunha KC, Sutton DA, Fothergill AW, et al. (2013). In vitro antifungal susceptibility and molecular identity of 99 clinical isolates of the opportunistic fungal genus Curvularia. Diagnostic Microbiology and Infectious Disease 76: 168–174.
Deng H, Tan YP, Shivas RG, et al. (2014). Curvularia tsudae comb. nov. et nom. nov., formerly Pseudocochliobolus australiensis, and a revised synonymy for Curvularia australiensis. Mycoscience 56: 24–28.
Khemmuk W, Shivas RG, Henry RJ, et al. (2016). Fungi associated with foliar diseases of wild and cultivated rice (Oryza spp.) in northern Queensland. Australasian Plant Pathology 45: 297–308.
Madrid H, da Cunha KC, Gene J, et al. (2014). Novel Curvularia species from clinical specimens. Persoonia 33: 48–60.
Manamgoda DS, Cai L, Bahkali AH, et al. (2011). Cochliobolus: an overview and current status of species. Fungal Diversity 51: 3–42.
Manamgoda DS, Cai L, Hyde KD (2012a). Two new species of Curvularia from nothern Thailand. Sydowia 64: 255–266.
Manamgoda DS, Cai L, Hyde KD (2012b). A taxonomic evaluation of the holomorphic species complex: Cochliobolus, Bipolaris and Curvularia through multilocus phylogeny. Fungal Diversity 56: 131–144.
Manamgoda DS, Rossman AY, Castlebury LA, et al. (2014). The genus Bipolaris. Studies in Mycology 79: 221–288.
Manamgoda DS, Rossman AY, Castlebury LA, et al. (2015). A taxonomic and phylogenetic re-appraisal of the genus Curvularia (Pleosporaceae): human and plant pathogens. Phytotaxa 212: 175–198.
Manamgoda DS, Udayanga D, Cai L, et al. (2013). Endophytic Colletotrichum from tropical grasses with a new species C. endophytica. Fungal Diversity 61: 107–115.
Marin-Felix Y, Groenewald JZ, Cai, L, et al. (2017). Genera of phytopathogenic fungi: GOPHY 1. Studies in Mycology xxxx.
Tan YP, Madrid H, Crous PW, et al. (2014). Johnalcornia gen. et. comb. nov., and nine new combinations in Curvularia based on molecular phylogenetic analysis. Australasian Plant Pathology 43: 589–603.
Zhang JZ, Li MJ (2009). A new species of Bipolaris from the halophyte Sesuvium portulacastrum in Guangdong Province, China. Mycotaxon 109: 289–300.