Species diversity of Colletotrichum infecting Annona spp. in Brazil

Anthracnose disease caused by Colletotrichum species is a limiting factor in the production and commercialization of annonaceous crops in different regions of the world. In this study, 96 Colletotrichum isolates were collected from soursop and sugar apple leaves showing anthracnose symptoms in commercial plantations of the state of Alagoas, northeastern region of Brazil. To assess initially the species diversity, the isolates were identified by phylogeny based on the sequences of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Representative strains were selected for further identification based on multigene phylogeny analysis using sequences of the internal transcribed spacer region (ITS), actin (ACT), chitin synthase (CHS-1), -tubulin (TUB2), calmodulin (CAL), histone3 (HIS3), glutamine synthetase (GS) and (GAPDH) genes. Morpho-cultural characterization and pathogenicity tests were also performed. These analyses allowed the identification of nine species: Colletotrichum brevisporum, C. cliviae, C. fructicola, C. gigasporum, C. gloeosporioides, C. karstii, C. siamense, C. theobromicola and C. tropicale. Until now, only C. fructicola, C. gloeosporioides and C. theobromicola had been associated with anthracnose of soursop and sugar apple in Brazil. C. brevisporum, C. cliviae and C. gigasporum species are also described for the first time on annonaceous species worldwide.