Caracterização molecular e morfocultural de Colletotrichum spp. associados à antracnose em Capsicum spp. no nordeste do Brasil

Abstract

Anthracnose is an important disease for solanaceous vegetables such as sweet peppers and chili peppers. The disease is caused by fungi of Colletotrichum genus that cause great losses in world production, both in the field and post-harvest, leading to losses of up to 100%. The aim of this study was to identify the species of the genus Colletotrichum through molecular characterization and morfocultual in Capsicum spp. Isolates were obtained from sweet peppers and chili peppers with symptoms of anthracnose, collected in municipalities in the states of Alagoas, Sergipe and Pernambuco. The thirty-eight isolates were initially analyzed based on the sequences of glyceraldehyde 3-phosphate dehydrogenase gene (GAPDH), to know the diversity of species present in these cultures. The identification of the isolates was confirmed with concatenated analysis of GAPDH genes, β-tubulin (TUB2) and ITS-rDNA region. For cultural characterization of the identified species, it was carried out the assessment of mycelial growth rate of isolated and observed the color of the colonies grown in synthetic BDA, after seven days. For morphological characterization, the length and width of 50 conidia and apressoria were measured. The identified species were subjected to cross-pathogenicity test in chili pepper, sweet pepper, tomatoes and eggplant, kept at 25 ° C in the dark. Species in at least four distinct genus Colletotrichum complexes are associated with anthracnose on fruits of Capsicum spp. in northeastern Brazil, and the specie C. scovillei from complex C. acutatum was most often found causing anthracnose in Capsicum spp. Chili pepper, sweet pepper, tomatoes and eggplant are part of the host range of C. scovillei, C. tropicale, C. siamense and C. truncatum.