Genetic and pathogenic diversity of colletotrichum gloeosporioides, the causal agent of cashew anthracnose (original) (raw)
Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is one of the most important diseases in cashew (Anacardium occidentale) cultivation. In this study, the genetic and pathogenic diversity of this microorganism isolated from cashew crops from Pernambuco State, Brazil, were evaluated by RAPD and ribosomal DNA-RFLP analysis. Based on the RAPD analysis, considerable genetic diversity was exhibited by the evaluated isolates, and the rDNA RFLP analysis by MspI restriction demonstrated polymorphisms among the isolates. Although both techniques were efficient and reproducible, RAPD indicated higher genetic variability among the isolates when compared with the rDNA RFLP analysis. The isolates were clustered in two groups using UPGMA analysis of the RAPD and RFLP data, with Group I subdivided into five subgroups and Group II into four subgroups. A pathogenicity test performed using detached cashew leaves showed that the isolates Cg02 and Cg03 were the most aggressive. Through RAPD and rDNA RFLP analyses, this study demonstrated a correlation between the genetic groups and geographical origin of the isolates; however, no correlation was found between these groups and pathogenicity. 251 rRNA gene, which involves an adjusted model showing a small specific polymorphism and a high general specific variability . The amplification of this region and its restriction is an important tool to describe the genetic variability of plant pathogenic fungi. This study aimed to evaluate the genetic variability of C. gloeosporioides isolates obtained from cashew trees in different regions of Pernambuco State, Brazil, using RAPD and rDNA-RFLP analysis and to determine the possible correlation between the region and pathogenicity level of the isolates.
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