The present work aimed to study the phenotypic and pathogenic diversity of 40 Colletotrichum isolates obtained from mango trees in the Northeast of Brazil and to identify different species of this pathogen, incitant of anthracnose, through the analysis of the ITS sequence of the ribosomal DNA. As for the morphologic and cultural characterization, the colonies of the isolates presented diversity in relation to color and aspect, being more common the color white-ash, characteristic of C. gloeosporioides. Expressive variations were not observed in the morphology of the 40 isolates. The conidia were predominantly hyaline and unicellular varying in shape from rod to cylindrical. All isolates produced appressoria of different shapes and in different amounts, and 10 isolates showed setae. In relation to mycelial growth and growth rate the isolates were classified in seven groups. Twenty-two isolates exhibited growth rate >10mm/day, considered typical of C. gloeosporioides species. The isolates were pathogenic to detached leaves of mango, inducing anthracnose symptoms such as dark lesions slightly depressed, and presenting variations of aggressiveness. In the specific identification based on the analysis of the ITS sequence of the ribosomal DNA, 36 isolates amplified with the primer CgInt, specific for C. gloeosporioides and with the primer ITS4. Isolates CM1, CM4, CM5 and CM10 did not amplify products for none of the specific primers, being identified as Colletotrichum spp. The results of this work demonstrate that Colletotrichum isolates obtained from mango trees present large morphophysiologic and pathogenic variability, and also that, possibly exists more than one species of Colletotrichum that causes anthracnose in mango trees in the Northeast of Brazil.
Mangifera indica; pathogenicity; rDNA; Glomerella cingulata
