A new Ophiodothella species associated with leaf spots on Annona squamosa in Brazil

Uma nova espécie de Ophiodothella causando manchas foliares em Annona squamosa no Brasil

COMMUNICATIONS COMUNICAÇÕES

A new Ophiodothella species associated with leaf spots on Annona squamosa in Brazil

Uma nova espécie de Ophiodothella causando manchas foliares em Annona squamosa no Brasil

José Luiz Bezerra^I; Francisco C.O. Freire^II; Dayse Andrade^I

^ICEPLAC/CEPEC/Seção de Fitopatologia, CEP 45600-970, Ilheus BA

^IILaboratório de Fitopatologia, Embrapa Agroindústria Tropical, CEP 60511-110, Fortaleza, CE, e-mail: [e-mail]

ABSTRACT

A new species of Ophiodothella, O. annonae (Phyllachoraceae, Ascomycetes) is described and illustrated. The fungus causes brown lesions on leaves of Annonae squamosa, which can fall off prematurely, and is characterized by fusiform, slightly curved, biguttulate ascospores with a conspicuous central concentration of cytoplasm. This is the first species of Ophiodotella found on leaves of Annonaceae in Brazil.

Additional keywords: Ascomycete, Phyllachoraceae, Ophiodothella annonae, taxonomy.

RESUMO

A nova espécie de ascomiceto Ophiodothella annonae (Ascomycetes: Phyllachoraceae) é descrita e ilustrada. O fungo causa manchas foliares em Annona squamosa. Folhas infectadas exibem lesões arredondadas de coloração marron-clara e com bordos enegrecidos, podendo cair prematuramente. O fungo apresenta ascósporos ligeiramente curvos, fusiformes, bigutulados e com uma concentração de citoplasma na região central. Esta é a primeira espécie de Ophiodothella encontrada em folhas de Annonaceae no Brasil.

Palavras-chave adicionais: ascomiceto, Phyllachoraceae, Ophiodothella annonae, taxonomia.

A severe leaf spot disease, caused by an Ophiodothella species, was detected during 2004 on Annona squamosa L. in the municipalities of Cascavel and Pacajus, in Ceará State (Brazil). The disease occurs mainly during the rainy season, from February to June, with incidence peaking in May. The infection appears first as small brown lesions scattered on the leaf blade. Under high humidity, lesions often coalesce, reaching up to 20 mm. Lesions are subcircular, pale brown with dark brown margins, usually showing ruptured central tissues, with 15 to 90 clypei (Figure 1). Premature leaf fall may occur in severely infected plants.

Fungi occurring on Annona in Brazil and South America have been reported by Viégas (1961), Mendes et al (1998) and Silva & Minter (1995). This article reports the occurrence of a new species of Ophiodotella on Annona squamosa in Brazil.

Infected leaves of Annona squamosa collected in the municipalities of Cascavel and Pacajus were placed in plastic bags and taken to the Plant Pathology Laboratory of Embrapa Agroindústria Tropical, in Fortaleza, State of Ceará (Brazil). After initial microscopic examination, duplicates were sent to the Plant Pathology Laboratory of CEPLAC, in Bahia State (Brazil). Sections of infected leaf tissues were cut using a freezing microtome and placed on slides containing a drop of lacto-fuchsin or lacto-cotton blue.

Taxonomy

Ophiodothella annonae Bezerra, F. Freire & D.M. Andrade sp. nov.

Laesiones ad 20 mm diam., brunneae, coalescentes, amphigenae. Conidiomata ad 224 µm diam., subglobosa vel depressa, nigra. Cellulae conidiogenae 9.6-12.8 x 2.0–2.4 µm, cylindricae sed leniter angustatae. Conidia 11.2-15.2 x 0.8-1.2 µm, cylindricae vel filiformia, aseptata, hyalina.

Partes denigrate 200-272 µm diam., uniloculatae. Asci 68-80 x 11.2-12.0 µm, cymbiformes, tenuitunicati, brevistipitati, apparato apicale praediti, octospori. Paraphyses 0.7-1.0 µm diam., ramosae, tenuitunicatae. Ascosporae 30-40 x 4.0-4.3 µm, fusiformes, curvatae, imbricatae, hyalinae, laeves, aseptate, intus 2-guttulatae.

HOLOTYPUS: CEPEC col. micol. 393, in foliis vivis Annonae squamosae (Annonaceae), Preaoca, Cascavel, Ceará, Brasil, 04° 84’’ 50.5’ S; 38º 22’ 1.8’’ W; altitude 45 m, 13/05/2004, leg. Francisco C.O. Freire.

Anamorph: conidiomata suglobose or flattened, dark brown, slightly erumpent, 120–224 µm wide, with a flat ostiole, mainly epiphyllous. Conidiogenous cells simple or branched at the base, tapering towards the apex, forming a palisade, 9.6–12.8 x 2.0–2.4 µm, subhyaline to light green, Conidia filiform, 11.2–15.2 x 0.8–1.2 µm, hyaline, smooth, 1-celled (Figure 2).

Teleomorph:clypei scattered, isolated, occasionally coalesced, mostly concentrated in lesion centers, black, slightly raised, 56–80 µm thick close to ostiole, thinner towards the margins, formed from host cuticle and epidermis plus fungus tissues and embedded in an amorphous melanized material. Perithecia subglobose to subpyriform, immersed, 137-214 µm wide, 239–289 µm high, ostiole inconspicuous, walls 20–30 µm thick, composed of subhyaline cells, textura angularis. Asci broadly cymbiform, unitunicate, thin-walled, evanescent, 8-spored, short-stalked, 68–80 x 11.2–12 µm, apex obtuse with a subapical inconspicuous ring. Paraphyses filamentous, branched, septate, 0.7–1.0 µm diam. Ascospores fusiform, hyaline, slightly curved, tapering gradually towards ends, 30–40 x 4–5 µm, 1-celled, thin and smooth-walled, biguttulate, with a conspicuous central concentration of cytoplasm (Figure 3).

The species Ophiodothella paraguariensis (Speg.) Höhn. occurs on Rollinia (family Annonaceae) in Paraguay. However, it differs from O. annonae in having larger clypei (260–320 µm), narrower perithecia (80–220 µm), and narrower, filiform, multiguttulate and longer (40-45 x 2–2.5 µm) ascospores (Hanlin et al., 1992).

Holotype: Brazil: Preaoca, Cascavel, Ceará, 04º 84’50.5’’S, 38º 22’1.8’’W; altitude 45 m, 13/05/2004, leg. Francisco C.O. Freire (CEPEC col. micol. 393 – Holotype).

Etymology: the epithet is derived from the host genus, Annona.

Distribution: Brazil; known only from the type locality.

ACKNOWLEDGMENTS

To Dr. Zofia Lawrence (CABI Bioscience. Egham, UK), thanks for her invaluable comments and suggestions.

Accepted for publication 15/12/2006

Author for correspondence: José Luiz Bezerra

• HANLIN, R.T., GOH, T-K & SCARSHAUG, A.J. A key to and descriptions of species assigned to Ophiodothella, based on the literature. Mycotaxon 44:103-126.1992.
• MENDES, M.A.S., SILVA, V.L., DIANESE, J.C., FERREIRA, M.A.S.V, SANTOS, C.E.N., NETO, E.G., URBEN, A.F & CASTRO, C. Fungos em plantas no Brasil. Brasília. EMBRAPA-SPI/EMBRAPA-CENARGEN. 1998.
• SILVA, M.S. & MINTER, D.W. Fungi from Brazil recorded by Batista and co-workers. 1995. Wallingford. CAB International. Mycological Papers 169.
• VIÉGAS, A.P. Índice de fungos da América do Sul. Campinas. Instituto Agronômico de Campinas. 1961.

Publication Dates

• Publication in this collection
  15 Mar 2007
• Date of issue
  Dec 2006

History

• Accepted
  15 Dec 2006
• Received
  15 Dec 2006