Caracterização de isolados de Colletotrichum gloeosporioides associados à antracnose do cajueiro

Abstract

The anthracnose, fungal disease caused by Colletotrichum gloeosporioides, stands out as an important disease of cashew (Anacardium occidentale), which may lead to losses of over 40% in production. The cashew nut is the most important agricultural product of the state of Ceará, about 350 thousand hectares, generating more than 100 thousand direct/indirect jobs and exports over 150 million dollars in almonds. It is also important for the states of Piauí and Rio Grande do Norte. There are few and outdated research about disease and the needs basic information for programs improvement and integrated management of diseases. By presenting large morphological and genetic variability, it is difficult to generalize basic aspects of the species. The aim of this study was to characterize populations of C. gloeosporioides occurring on cashew trees in various regions of Brazil. Used 220 isolates obtained from cashew leaves, from 22 different areas of the states: Amazonas, Ceará, Maranhão, Paraíba, Pernambuco, Piauí, Rio Grande do North and São Paulo. Proceeded with pathogenic tests and molecular markers species-specific to all isolates. Then a representative from each collection area was selected to perform the other ratings, which are: morphological, molecular, epidemiological and physiological. The species-specific markers β-tubulin and ITS, noted the existence of only one group of 10 isolates of the same area, not being confirmed for C. gloeosporioides or C. acutatum, but morphological characteristics of C. gloeosporioides. Using seven primers ISSR markers and 100 representatives in 22 areas, it was possible identify the formation of four distinct genetic groups of C. gloeosporioides, where the unmarked isolated by ITS or β-Tubulin, not was contained in one or in groups. With the pathogenic test using 5 clones, it was possible to distinguish three groups and another 3 isolates distinct from other. Conclude that the species C. gloeosporioides is prevalent in cashew plantations in the areas studied.