Abstract Detail

Mycological Section

Firmino, Andre Luiz [1], Pereira, Olinto Liparini [2].

A new family of Asterinales (Dothideomycetes) associated with necrotic leaves of the bromeliad Alcantarea imperialis, from Minas Gerais, Brazil.

The Asterinales is a poorly known order comprising 2 families, Asterinaceae and Parmulariaceae. In 2014, infected leaves of the bromeliad Alcantarea imperialis showing black colonies possibly belonging to Asterinales were collected on the campus of the Universidade Federal de Viçosa, Minas Gerais, Brazil. Leaves were photographed, dried, and examined under an Olympus SZ 40 stereomicroscope. Observations and measurements were made with an Olympus BX 53 microscope equipped with a digital camera (Q-Color 5 Olympus). Biometric data were based on 30 measurements of structures. DNA was extracted and the 28S rDNA amplified for molecular analysis. The fungus was shown to be a new Asterinales family with colonies epiphyllous, circular to irregular, single to confluent, black, 1–6 mm diam.; External mycelium straight to flexuous, branching irregular, pale brown, septate, hyphal cells cylindrical to isodiametric, 2.5–4 µm diam., smooth; Apressoria absent; Internal mycelium extensive, mainly in the epidermal cells extending to the subepidermal cells. The whole internal mycelium is intercellular and no haustoria are produced in the host cells 2.5–7.5 μm, pale brown, smooth; Hysterothecia superficial, develop above surface mycelium, linear to V–Y shaped, single to confluent, fringed at margins, 120–200 × 80–110 μm, brown to dark brown, open with a longitudinal fissures, with arrow-like setae, 90–162.5 × 3–4 μm; Pseudoparaphyses not observed. Scutellum radiate, composed of dichotomously branched filaments, scutellum cells isodiametric to cylindrical; Asci bitunicate, fissitunicate, upright and parallel, globose to ovoid, 8-spored, hyaline, 25–34 µm diam.; Ascospores 2–celled oblong-clavate, straight, ends rounded, constricted at central septum, hyaline, becoming pale brown to brown at maturity, smooth, 18–19.5 × 7–8 µm. Anamorph absent. Based on the phylogenetic analysis of the 28S rDNA sequences, the fungus grouped with the order Asterinales, however in a well distinct clade, being phylogenetically distinct from the Asterinaceae and Parmulariaceae families. This new family is similar to Asterinaceae, especially to the genus Trichamelia, however differs by its internal mycelium, the absence of apressoria and grow only in necrotic areas of the leaves. The new family will be proposed, according the International Code of Nomenclature for Algae, Fungi and Plants. Financial support: CNPq, CAPES and FAPEMIG.

1 - Universidade Federal de Vicosa, Fitopatologia, Av. Peter Henry Rolfs, Vicosa, MG, 36570900, Brazil
2 - Universidade Federal de Vicosa, Fitopatologia, Av. Peter Henry Rolfs, Fitopatologia, Vicosa, MG, 36570900, Brazil

Keywords:
Asterinales
Tropical fungi
taxonomy
Phylogeny
Parmulariaceae.

Presentation Type: Oral Paper:Papers for Sections
Session: 40
Location: Salon 1/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 11:45 AM
Number: 40007
Abstract ID:1148
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student