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Instituto de Ecología y Sistemática, Ministerio de Ciencias, Tecnología y Medio Ambiente, Carretera de Varona Km 3.5, Capdevila Boyeros, AP 8029, CP 10800, Ciudad de la Habana, Cuba
Alberto Stchigel
Josep Guarro 1
Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, and Institut d'Estudis Avançats, Universitat Rovira i Virgili, C/ Sant Llorenç 21, 43201 Reus, Spain
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSTAXONOMYLITERATURE CITED |
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Chaetomium macrostiolatum sp. nov., Chaetomium olivicolor sp. nov. and Chaetomium tarraconensis sp. nov. isolated from Nigerian, Indian, and Spanish soils respectively, are described and illustrated. The first species is characterized by ascomata with a very broad ostiole and yellow hairs, and limoniform ascospores; the second by its thermotolerant growth, inconspicuous and short straight ascomatal hairs and fusiform ascospores; and the last by its unusual, irregularly-shaped ascospores and subglobose ascomata with flexuous to undulate, unbranched ascomatal hairs.
Key words: Ascomycetes, Chaetomiaceae, Sordariales, systematics
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYLITERATURE CITED |
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, Cannon 1986
, Cano and Guarro 1987
, Carris and Glawe 1987
, Moustafa and Ess El-Din 1988
, Abdullah and Al-Bader 1989
, Horie and Udagawa 1990
, Pande and Rao 1990
, Udaiyan and Hosagoudar 1991
, Abdullah and Zora 1993
, Udagawa et al 1994
, Gené and Guarro 1996
, Decock and Hennebert 1997
, Udagawa et al 1997
), and are found in the most diverse substrates and geographic regions. Chaetomium species are characterized by superficial ascomata, usually covered with hairs or setae mainly surrounding a rather broad apical ostiolar pore, and attached to the substrate by rhizoidal hyphae. Their ascospores are aseptate, brown or gray-olivaceous with one or two germ pores. During the course of a study of soil fungi from different regions of the world we have isolated numerous strains of this genus, some of them belonging to undescribed species. In this paper three new species collected from soil samples of Nigeria, India, and Spain respectively are described and illustrated. |
MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYLITERATURE CITED |
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The samples were mainly collected from the Ao horizon using sterilized polyethylene bags. These were sealed with a rubber band and labelled. The samples were stored in the laboratory at 4–7 C until used. The samples from India and Spain were handled by a modification of Furuya and Naito's method (1979)
, described previously by Stchigel et al (2001)
. The sample from Nigeria was treated with 2% (p/v) phenol in water for 10 min and cultured on potato carrot agar (PCA, Difco) with chloramphenicol (50 mg/L) at room temperature (22–25 C), under 12 h of darkness alternating with 12 h of cool white fluorescent light. The morphological characteristics of the colonies were studied on Petri dishes of 90 mm diam containing oatmeal agar (OA; Difco), and PCA at temperatures of 15 C, room temperature, 37 C, 45 C, 48 C, and 50 C. Color notations in parentheses are from Kornerup and Wanscher (1984)
. Fungal structures were measured in lactophenol, and mounted in Melzer's reagent to observe dextrinoid reaction of the ascospores. Photomicrographs were obtained with a Leitz Dialux 20 EB microscope. Scanning electron microscopy techniques were described previously by Figueras and Guarro (1988)
. Dried and living cultures have been preserved in the culture collections and herbarium indicated in the text.
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TAXONOMY |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYLITERATURE CITED |
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Mycelium ex hyphis hyalinis vel subhyalinis, septatis, laevibus, 1–2 µm diam compositum. Coloniae in agaro farinae avenaceae celeriter crescentes, planae, ex mycelio vegetativo diffuso et submerso constantes, numerosis ascomatibus formantes, leniter zonatae, olivaceo-brunneae; reversum olivaceo-brunneum. Ascomata superficialia, pallido olivacea vel olivacea, subglobosa vel ovoidea, 100–140 x 80–110 µm, tarde maturescentia, ostiolum latum, usque ad 50 µm diam. Peridium pallido brunneum, translucidum, membranaceum, cum textura angularis vel textura epidermoidea. Pili terminales numerosi, longi, flavescentes vel pallido brunnei, ad apicem recurvati, simplices, usque ad 200 µm longi et 2–3.5 µm lati, septati, crassitunicati, tenuiter verrucosi, regulariter septati. Pili laterales ad apicem recurvati. Asci fasciculati, 8-spori, clavati et longistipitati, 35–58 x 9–17 µm, evanescentes. Paraphysis nulla. Ascosporae pallido brunneae vel leniter brunneae, limoniformes, inaequales, complanatae, 10–13 x 7–10 x 6.5–7.5 µm, biapiculatae, laeves, crassitunicatae, cum poro germinalibus apicali visibile. Anamorphosis absens.
Mycelium composed of hyaline to subhyaline, septate, smooth hyphae, 1–2 µm diam. Colonies on OA growing rapidly, attaining a diameter of 55–60 mm after 14 d at room temperature, flat, consisting of spreading, submerged mycelium, and with a granular appearance due to the abundant ascomata, surrounded and covered by a loose network of aerial hyphae, slightly zonate, olive brown (M.4F6 to M.4F8); reverse olive brown (M. 4F6 to M. 4D7). Ascomata superficial, olivaceous, subglobose to ovoid, 100–140 x 80–110 µm, firmly attached to the substratum by a basal tuft of hyphae, maturing in or within 14–20 d; ostiole very broad, up to 50 µm diam. Peridium pale brown, translucent, membranaceous, 1–2 layered, 4–5 µm thick, textura angularis to textura epidermoidea, composed of polygonal to irregular cells, measuring 5–10 µm diam. Terminal hairs numerous, mostly around the ostiole, yellow to light brown in reflected light, arcuate or recurved at the apex, unbranched, up to 200 µm long, 2–3.5 µm diam at the base, thick-walled, verruculose, regularly septate. Lateral hairs less abundant, recurved at the apex. Asci fasciculate, 8-spored, clavate and long stipitate, 35–58 x 9–17 µm, evanescent, without apical structures. Paraphyses absent. Ascospores 1-celled, dextrinoid when young, pale brown to mid brown, limoniform, often asymmetrical and bilaterally flattened, 10–13 x 7–10 x 6.5–7.5 µm, biapiculate, smooth- and thick-walled, with a conspicuous apical germ pore. Anamorph absent.
On PCA at room temperature, colonies attaining a diameter of 30–38 mm in 14 d, granulose to powdery, strongly zonate, yelow (M. 4A3); reverse yellowish-white (M. 4A2). On OA and PCA at 15 C and 37 C, colonies growing very slowly, attaining a diameter of 20–25 mm in 14 d; aspect identical to those on OA at room temperature. Ascomata less abundant. No growth was observed at 45 C.
Specimens examined. NIGERIA: Ihenyi Eha-Amufu, Isi-uzo, Enugu state, from forest soil, 12-VI-1997, col. A. M. Stchigel, isol. A. M. Stchigel (HOLOTYPE: IMI 382896; ISOTYPE: FMR 6780). Living cultures ex type: IMI 381870, CBS 102435, MUCL 43147, FMR 6780.
Other species examined. Chaetomium flavigenum CBS 337.67; C. turgidopilosum CBS 169.52; C. lentum CBS 339.67, CBS 644.83; C. seminudum CBS 779.71, CBS 780.71; C. longicolleum CBS 155.55, CBS 119.57; C. floriforme IMI 368520; C. fusiforme FMR 670, FMR 673; C. gracile CBS 146.60; C. lucknowense CBS 243.84; C. malaysiensis CBS 669.82; C. ampullare FMR 725; C. homopilatum CBS 157.55; C. sphaerale FMR 726.
Etymology. The epithet macrostiolatum refers to the wide ostiole.
The presence of ascomata with a broad ostiole and yellow hairs, and limoniform, bilaterally flattened ascospores clearly separates Chaetomium macrostiolatum from all previously described species of the genus. Species with similar hairs are C. fusiforme Chivers, C. aureum Chivers, C. flavigenum van Warmelo, C. turgidopilosum Ames, C. lentum van Warmelo, C. gracile Udagawa, C. lucknowense Rai & Tewari, and C. cupreum Ames (Seth 1970
). However, the ascospores of these species are clearly different. In C. fusiforme they are fusiform; in C. aureum and C. flavigenum, fusiform to navicular; in C. turgidopilosum and C. lentum, ellipsoidal; in C. gracile, ellipsoidal to broadly fusiform; in C. lucknowense, ovate to ellipsoidal; and in C. cupreum, reniform to lunate (Arx et al 1986
). Several species of Chaetomium, such as C. malaysiensis (D. Hawksw.) Arx, C. seminudum Ames, C. longicolleum Krzem. & Badura, C. cuyabenoensis Decock & Hennebert, C. ampullare Chivers, C. homopilatum Omvik, C. sphaerale Chivers, and C. floriforme Gené & Guarro, also have limoniform, bilaterally flattened ascospores similar to those of the new species. However, with the exception of C. floriforme and C. sphaerale, the species mentioned have ampulliform ascomata with a conspicuous neck formed by fused hairs, sometimes very long, such as in C. longicolleum (Arx et al 1986
, Hawksworth 1975
) and C. cuyabenoensis (Decock and Hennebert 1997
). For this reason and by the production of a Botryotrichum-like anamorph some of these species have been placed by Hawksworth (1975)
in the closely related genus Farrowia D. Hawksw. Chaetomium sphaerale is easily differentiated from C. macrostiolatum by its flexuous ascomatal hairs and smaller ascospores (7.5–9 x 6–7 x 4–5 µm), and from C. floriforme by its ascomatal hairs, which are constricted at the septa and disarticulate when mature, its smaller ascospores (7–8.5 x 6–7.2 x 5–6 µm), and the presence of a Humicola-like anamorph.
Chaetomium olivicolor Kendra Rodríguez, Stchigel & Guarro, sp. nov. Figs. 12 –19
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Mycelium ex hyphis hyalinis vel subhyalinis, septatis, laevibus, 1–2 µm diam compositum. Coloniae in agaro farinae avenaceae celeriter crescentes, planae, ex mycelio vegetativo diffuso et submerso constantes, cum numerosis ascomatibus formantes, leniter zonatae, olivaceo-brunneae; reversum olivaceo-brunneum, cum pigmento diffuso olivaceo-viridi. Ascomata superficialia vel immersa, flavo-grisea, subglobosa vel lageniformia, 92–210 x 85–180 µm, celeriter maturescentia, ostiolum usque ad 23 µm latum. Peridium pallide olivaceo-brunneum vel atro-brunneum, opacum, membranaceum, cum textura angularis. Pili terminales numerosi, pallido-brunnei, recti, simplices, usque ad 125 µm longi et 4–5 µm lati, incrassati, tenuiter verrucosi, septati, versus apicem gradatim angustati et pallescentes. Pili laterales simili sed minus numerosi quam terminales. Asci fasciculati, 8-spori, clavati, et brevistipitati, 20–50 x 5–15 µm, evanescentes. Paraphysis nulla. Ascosporae coeruleo-brunneae vel brunneae, fusiformes vel latus fusiformes, saepe inaequales, 9.5–12 x 5–7 x 5–6 µm, laeves, crassitunicatae, cum poro germinali apicali vel subapicali visibile. Anamorphosis absens.
Mycelium composed of hyaline to subhyaline, septate, smooth hyphae, 1–2 µm diam. Colonies on OA growing rapidly, covering the Petri dish surface after 14 d at 45 C, flat, consisting of spreading, submerged vegetative mycelium, and with granular appearance due to the abundant ascomata, surrounded and covered by a loose network of aerial hyphae, slightly zonate, olive brown (M. 4F2 to M. 4F6); reverse similar in color to colony surface; diffusible olive-green pigment (M. 1F4) abundant. Ascomata superficial or immersed, yellowish-gray, subglobose to ampulliform, 92–210 x 85–180 µm, maturing in 5 d, firmly attached to the substratum by a basal tuft of hyphae, ostiole up to 23 µm diam, papillate. Peridium pale olive-brown to dark brown, opaque, membranaceous, 1–2 layered, 2–4 µm thick, textura angularis, with polygonal cells measuring 7–15 µm diam. Terminal hairs numerous disposed mostly around the ostiole, pale brown, straight, unbranched, up to 125 µm long, 4–5 µm diam near the base, thick-walled, verrucose, regularly septate, tapering and becoming paler towards the tip. Lateral hairs similar and less abundant. Asci fasciculate, 8-spored, clavate and short stipitate, 20–50 x 5–15 µm, evanescent, without apical structures. Paraphyses absent. Ascospores 1–celled, bluish-brown to brown, fusiform to broadly fusiform, sometimes asymmetrical, 9.5–12 x 5–7 x 5–6 µm, smooth- and thick-walled, with a conspicuous apical or subapical germ pore, often with a paler spot suggesting a second germ pore at the opposite end. Anamorph absent.
On PCA at 45 C, colonies covering the Petri dish surface in 14 d, similar to those on OA although less zonate and with lower production of pigment. On OA and PCA, at 37 C, colonies growing rapidly, covering the Petri dish surface in 14 d, with characteristics similar to those on OA at 45 C. Ascomata abundant. At room temperature and 48 C, growing very slowly, attaining a diam of 2.5–3.5 mm in 14 d, and ascomata are not produced. No growth was observed at 15 C and 50 C.
Specimen examined. INDIA: Delhi, from garden soil, 11-VII-1996, col. J. Gené and J. Mariné, isol. A. M. Stchigel (HOLOTYPE: IMI 382895; ISOTYPE: FMR 6779). Living cultures ex type: IMI 381869, CBS 102434, MUCL 43148, FMR 6779.
Other species examined. Chaetomium virescens CBS 554.83; C. hispanicum CBS 234.82, CBS 550.83.
Etymology. The epithet olivicolor refers to the olive green color of the diffusible pigment.
Chaetomium olivicolor is similar to C. virescens (Arx) Udagawa. However, the latter has two germ pores and more regular ascospores. Chaetomium virescens var. thielavioideum (Chen) P. Cannon has roughly regular-shaped ascospores with one terminal germ pore, although the ascospore size is somewhat larger (12–16.5 x 5.5–7 µm) (Cannon 1986
). Chaetomium hispanicum Guarro & Arx also shows some similarities with the new species, but differs by more regular and longer (13–15 x 6.5–8 µm) ascospores. In addition, the ascomatal hairs of these two species are flexuous and longer than those of C. olivicolor. The new species, as well as other species of Chaetomium (Mouchacca 1997
) is also characterized by its thermotolerant growth. Numerous species produce green diffusible pigment such as C. bostrychodes Zopf, C. convolutum Chivers, C. elatum Kunze, C. globosum Kunze, C. gracile Udagawa, C. indicum Corda, C. madrasense Natarajan, C. megalocarpum Bainier, C. raii Malhotra & Mukerji, C. robustum Ames, C. variosporum Udagawa & Horie (Udagawa et al 1997
) and C. virescens but, the remaining morphological features are very different from those of C. olivicolor.
Chaetomium tarraconensis Stchigel, Kendra Rodríguez & Guarro, sp. nov. Figs. 20 –29
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Mycelium ex hyphis hyalinis vel subhyalinis, septatis, laevibus, 3–5 µm diam compositum. Coloniae in agaro farinoe celeriter crescentes, numerosis ascomatibus formantes, olivaceo-brunneae; reversum olivaceo-brunneum. Ascomata superficialia vel immersa, subglobosa, 155–275 x 130–205 µm, grisea, tarde maturescentia, ostiolata. Peridium pallido brunneum vel brunneum, translucidum, membranaceum, cum textura epidermoidea. Pili terminales cum longitudinibus inaequalibus, pallido brunnei, flexuosi vel undulati, simplices, usque ad 164 µm longi et 4–6 µm lati, incrassati, conspicum verrucosi, septati, ad apicem gradatim pallescentes. Pili laterales plerumque breviores quam terminales. Asci fasciculati, 8-spori, clavati, et longistipitati 35–65 x 10–17.5 µm, evanescentes, Paraphysis nulla. Ascosporae brunneae, irregulares, saepe latae ellipsoideae vel ovoideae, plerumque inaequales, complanatae, 9–14 x 7–11 x 9–9.5 µm, laeves, valde crassitunicatae, cum poro germinali marginali visibiles. Anamorphosis absens.
Mycelium composed of hyaline to subhyaline, septate, smooth hyphae, 3–5 µm diam. Colonies on OA growing rapidly, covering the Petri dish surface after 14 d at room temperature, with sparse aerial mycelium, producing abundant ascomata, olive brown (M. 4D4–M. 4E7); reverse similar in color to colony surface. Ascomata superficial to immersed, subglobose, 155–275 x 130–205 µm, gray, maturing in 20 d. Peridium pale brown to brown, translucent, membranaceous, 3–4 layered, 8–10 µm thick, textura epidermoidea. Terminal hairs of different length, sparse, pale brown, flexuous to undulate, unbranched, up to 164 µm long, 4–6 µm diam at the base, thick-walled, coarsely roughened, septate, gradually paling to the tip. Lateral hairs practically indistinguishable from the terminal ones, although generally the former are shorter. Asci fasciculate, 8-spored, clavate, and long stipitate, 35–65 x 10–17.5 µm, evanescent, without apical structures. Paraphyses absent. Ascospores 1-celled, dextrinoid when young, brown when mature, irregular in shape, often broadly ellipsoidal to ovoid, usually asymmetrical, bilaterally flattened, with a paler longitudinal band, 9–14 x 7–11 x 9–9.5 µm, smooth, thick-walled, with an subapical to lateral germ pore, and often with a pale spot suggesting a second germ pore in the opposite pole. Anamorph absent.
On PCA at room temperature, colonies attaining a diameter of 60–64 mm in 14 d, similar to those on OA but with fewer ascomata. On OA and PCA at 15 C, colonies growing very slowly, cream colored. Ascomata absent. At 37 C, growth is nil.
Specimen examined. SPAIN: Tarragona, from soil, 13-XI-1997, col. A. I. Diez and M. Goméz, isol. A. M. Stchigel (HOLOTYPE: IMI 382893; ISOTYPE: FMR 6638). Living cultures ex type IMI 380425, CBS 101882, MUCL 43149, FMR 6638.
Other species examined. Chaetomium megalocarpum IMI 075851.
Etymology. The epithet tarraconensis refers to the name of the place of collection.
The presense of subglobose ascomata with flexuous to undulate hairs of different length, and the typical morphology of the ascospores are diagnostic characteristics for C. tarraconensis. Chaetomium myricicola Horie & Udagawa (Horie and Udagawa 1990
) and C. megalocarpum (Arx et al 1986
) have ascospores with similar shape and size as those of the new species (10–14 x 8–11 µm in C. myricicola, and 12–16 x 10–14 x 8–12 µm in C. megalocarpum). However, they can be easily differentiated because C. megalocarpum has ascospores without longitudinal paler band, and with two germ pores, one at each end, and its ascomatal hairs are longer (up to 673 µm) and more numerous. Chaetomium myricicola has cylindrical asci (ascospores uniseriate) and different terminal hairs, thus straight to flexuous in their basal part, then becoming coiled. Chaetomium umbratile Udagawa, Toyaz. & Yaguchi (Udagawa et al 1997
), also has similar ascospores, but differs in having two types of ascomatal hairs: i) short, straight, unbranched and rigid and ii) long, sinuous or loosely spiral and irregularly branched.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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Accepted for publication May 25, 2001.
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LITERATURE CITED |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYLITERATURE CITED |
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Abdullah SK, Zora SB., 1993 Chaetomium mesopotamicum, a new thermophilic species from Iraqi soil Crypt Bot 3:387-389
Arx JA von, Guarro J, Figueras MJ., 1986 The Ascomycete genus Chaetomium Beih Nova Hedwigia 84:1-162
Cannon PF., 1986 A revision of Achaetomium, Achaetomiella and Subramaniula, and some similar species of Chaetomium Trans Br Mycol Soc 87:45-76
Cano J, Guarro J., 1987 Soil ascomycetes from Spain XII Nova Hedwigia 44:543-546
Carris LM, Glawe DA., 1987 Chaetomium histoplasmoides, a new species isolated from cysts of Heterodera glycines in Illinois Mycotaxon 29:383-391
Decock C, Hennebert GL., 1997 A new species of Chaetomium from Ecuador Mycol Res 101:309-310
Figueras MJ, Guarro J., 1988 A scanning electron microscopic study of ascoma development in Chaetomium malaysiense Mycologia 80:298-306
Furuya K, Naito A., 1979 An effective method for isolation of Boothiella tetraspora from soil Trans Mycol Soc Japan 20:309-311
Gené J, Guarro J., 1996 A new Chaetomium from Thailand Mycol Res 100:1005-1009
Hawksworth DL., 1975 Farrowia, a new genus in the Chaetomiaceae Persoonia 8:167-185
Horie Y, Udagawa S., 1990 New or interesting Chaetomium species from herbal drugs Trans Mycol Soc Japan 31:249-258
Kornerup A, Wanscher JH., 1984 Methuen Handbook of Color. 3rd ed London: Erye Methuen. 252 p
Mouchacca J., 1997 Thermophilic fungi: Biodiversity and taxonomic status Cryptog Mycol 18:19-69
Moustafa AF, Ess El-Din., 1988 Chaetomium sinaiense sp. nov., a new soil ascomycete from Egypt Can J Bot 67:3417-3419
Pande A, Rao VG., 1990 Ascomycetes of western India—XIV J Econ Tax Bot 14:157-161
Seth HK., 1970 A monograph of the genus Chaetomium Beih Nova Hedwigia 37:1-133
Stchigel AM, Cano J, Mac Cormack W, Guarro J., 2001 Antarctomyces psychrotrophicus gen. et sp. nov., a new ascomycete from Antarctica Mycol Res 105:377-382
Udagawa S, Uchiyama S, Kamiya S., 1994 Two new species of pyrenomycetous Ascomycetes from New Caledonia Mycoscience 35:319-325
Udagawa S, Toyazaki N, Yaguchi T., 1997 A new species of Chaetomium from house dust Mycoscience 38:399-402
Udaiyan K, Hosagoudar VS., 1991 Some interesting fungi from the industrial water cooling towers of Madras-II J Econ Tax Bot 15:649-667
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