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On-line version ISSN 1678-4405
Braz. J. Microbiol. vol.38 no.4 São Paulo Oct./Dec. 2007
Hemibeltrania urbanodendrii sp. nov. and Pseudobeltrania angamosensis: new fungal records from the brazilian tropical seasonal semi-deciduous montane forest
Hemibeltrania urbanodendrii sp. nov. e Pseudobeltrania angamosensis: novas ocorrências fúngicas da floresta tropical estacional semidecidual montana brasileira
Ronaldo de Castro FernandesI; Denise Castro Lustosa I; Robert Weingart BarretoI*; José Luiz BezerraII
IDepartamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, MG, Brasil
IIComissão Executiva do Plano da Lavoura Cacaueira, Centro de Pesquisa do Cacau, Itabura, BA, Brasil
The new species Hemibeltrania urbanodendrii, associated to leaf-spots on Urbanodendron verrucosum (Lauracea) and Pseudobeltrania angamosensis, associated with leaf-spots on Virola gardneri (Myristicaceae), are recorded for the first time in Brazil. They represent additions to the mycobiota of the Tropical Seasonal Semi-Deciduous Montane Forest in Viçosa (Minas Gerais, Brazil), a highly threatened ecosystem.
Key-words: Beltrania-like fungi; Urbanodendron verrucosum; Virola gardneri, biodiversity, fungal diversity, mycobiota
Novas ocorrências de fungos relacionados a manchas foliares são apresentadas: Hemibeltrania urbanodendrii sp. nov., associado a Urbanodendron verrucosum (Lauracea) e Pseudobeltrania angamosensis, associado a Virola gardneri (Myristicaceae). Eles representam adições à micobiota da Floresta Tropical Estacional Semidecidual Montana de Viçosa (Minas Gerais), um ecossistema fortemente ameaçado.
Palavras-chave: Urbanodendron verrucosum; Virola gardneri, biodiversidade, diversidade fúngica, micobiota
Although several publications deal with the flora of the Brazilian tropical seasonal semi-deciduous montane forests in the state of Minas Gerais (5-8), very little is known about the fungi occurring in this highly endangered ecosystem. In December 2003, an effort to list and describe the fungi occurring on a preserved fragment of forest (Mata do Seu Nico) located in the municipality of Viçosa was started. This has yielded an increasing list of mycological novelties either for Brazil or worldwide, some of which have already been published(9,10). In this paper two newly recorded Beltrania-like fungi associated to leaf-spots on native plants occurring in this site are described.
Leaves bearing leaf-spot symptoms were collected and taken to the lab for further exams. Fresh material was examined under a dissecting microscope and microscope slides were prepared in lactophenol from sporulating lesions. Examinations and illustrations were made with a light microscope (Olympus BX-50) fitted with a drawing tube. Leaves bearing fungal structures were dried in a plant press and deposited in the local herbarium (Herbarium VIC). The fungi were identified at the generic level with the help of published keys for dematiaceous hyphomycetes (2).
One fungus was collected in association with Urbanodendron verrucosum (Nees) Mez (Lauracea) and easily identified as a member of Hemibeltrania but had features clearly separating it from the known species in the genus. A new name is proposed for this taxon which is described below:
Hemibeltrania urbanodendrii sp. nov. (Fig. 1)
Etymology: from the host genus Urbanodendron.
Maculae minutae, atro-brunneae, irregularis, nervus centralis sequens, 0.2-0.7 x 0.2-0.3 mm diam; mycelium internum exiguum; mycelium externum nullum; conidiophora solitaria, cylindracea, recta, simplicia, basi lobata, 55-106 x 4-6 mm, 1-3 septata, levia, brunnea; cellulae conidiogenae polyblasticae, terminalis, deinde intercalares, sympodiales, 10-35 x 4-6 mm, subhyalinae; conidia solitária, biconica vel subrombica, 12-25 x 6-10 mm, leviter brunnea, fasciata, continua, levia.
Lesions on living leaves, initially small, elongate, necrosed areas, grayish with dark margin, becoming irregular to sublosangular, 0.2-0.7 x 0.2-03 mm, sometimes coalescing and extending along the whole length of the midrib. Internal mycelium branched, septate, pale brown. External mycelium absent. Conidiophores isolate, cylindrical, straight to somewhat sinuose, arising from lobed basal cells, unbranched, 55.0-106.0 x 4.0-6.0 mm, 1-3 septate, smooth, chestnut brown. Conidiogenous cells terminal, holoblastic, cylindrical, 10-35 x 4-6 mm, ending in an obtuse tip bearing 1-5 small, short denticles, smooth, subhyaline. Conidia isolate, oval, obovoid, biconic to limoniform, 12-25 x 6-10 mm, pale brown, aseptate, smooth, with small unthickened truncate scars or short peduncles.
Material examined: BRAZIL, state of Minas Gerais, Viçosa, Mata do Seu Nico, 9th Dec 2003, VIC 30450.
Keys to species of Hemibeltrania are available in the literature (1) and a recent publication covering specimens in this genus collected in Brazil also includes a key to the species in the genus (3). The closer species to H. urbanodendrii are H. nectandrae (Batista & Maia) Pirozynski and H. cinnamomi (Deighton) Pirozynski, but the new species differs from H. nectandrae by two independent characters: H. nectandrae has branched conidiophores and conidia which are 10-14 mm wide, while the new species has unbranched conidiophores and conidia that are 6-10 mm wide. Although H. nectandrae was also described from leaves of Nectandra sp. which, as U. verrucosum is also a member of the Lauraceae, from Brazil, the morphological differences that were observed justify the recognition of H. urbanodendrii as a separate taxon. Hemibeltrania cinnamomi was described from living leaves of cinnamon, from Sierra Leone (Africa). Similarly to H. nectandrae this species also attacks a member of the Lauraceae and also differs from the new species by having wider conidia (10-12 mm) and branched conidiophores.
The second Beltrania-like species to be found was associated to leaf spots on Virola gardneri (A.DC.) Warb. (Myristicaceae). The fungus fit well into the genus Pseudobeltrania. Its idenfication and description are presented below:
Pseudobeltrania angamosensis Matsushima, Mycological Memoirs 8: 1-44, 1995 (Fig. 2).
Lesions irregular pale brown with a dark center, 4-6.5 mm diam. Internal mycelium branched, septate, pale brown. External mycelium absent. Conidiophores in fascicles, arising from lobed basal cells, cylindrical, straight, branched, 75.0-142.5 x 4.5-7.5 mm, 3-5 septate pale brown, smooth. Conidiogenous cells terminal, holoblastic, poliblastic, proliferating simpodially, cylindrical, 18.0-48.0 x 4.5-6.0 mm, pale brown, conidiogenous loci conspicuous, denticulate, 2-7 per cell, 1-2 mm diam, unthickened, not darkened. Conidia isolate, holoblastic, biconic,16.5-30.0 x 10.5-15.7 mm, pale brown with a pale median transversal belt, scar unthickened, not darkened, 1-2 mm diam, eguttulate, smooth.
Material examined: BRAZIL, state of Minas Gerais, Viçosa, Mata do Seu Nico, 8th Dec. 2003, VIC 30449.
Pseudobeltrania angamosensis was previously known only from the type locality where it was found associated to petioles of an unidentified palm in Peruvian Amazon. This new, and very disjunct geographic record, on a dicotiledenous host suggests that this fungus has a wide distribution in South America on a wide range of plant substrates.
The authors thank Marcio Luiz Batista for identification of plants during the field work and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support.
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Submitted: March 07, 2007; Returned to authors for corrections: May 19, 2007; Approved: September 20, 2007.