Caracterização de espécies de colletotrichum associadas a flores tropicais no estado de Alagoas

Abstract

Tropical flowers are a profitable and expanding business worldwide and are important to floriculture due beauty and durability. Anthracnose is among the most important diseases of tropical flowers due to losses in production. The objectives of this work were: identify Colletotrichum species obtained from tropical flowers (Heliconia spp., Anthurium sp. and Alpinia sp.) through molecular and morpho-cultural characterization, as well as to evaluate the cross-pathogenicity. Thirty four isolates were obtained from three production fields in the state of Alagoas. Partial sequence of the glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) was amplified for a preliminary identification of the isolates. Posteriorly, representative isolates from each specie were chosen based on haplotype, and had other genomic regions amplifed and sequenced using: Chitin synthase (CHS-1), the ITS-rDNA region, Actin (ACT), Calmodulin (CAL) and β-Tubulin (TUB2). For morpho-cultural characterization, were measured the length and width of fifty conidia and appressoria, as well as the rate of mycelial growth and colonial coloring. Were identified three species belonging to Colletotrichum gloeosporioides complex (C. theobromicola, C. tropicale and C. siamense), and one isolated, named Colletotrichum sp., wich did not grouped in any complex already described. The C. siamense was the most frequent specie causing anthracnose in tropical flowers. All species were pathogenic, both in their host of origin and the possible hosts evaluated