PCR-based detection and characterization of the fungal pathogens Colletotrichum gloeosporioides and Colletotrichum capsici causing anthracnose in papaya (Carica papaya l.) in the Yucatan peninsula.

Colletotrichum gloeosporioides is the common causal agent of anthracnose in papaya (Carica papaya L.) fruits, and infection by this fungal pathogen results in severe post-harvest losses. In the Yucatán peninsula (Mexico) a different Colletotrichum species was isolated from papaya fruits with atypical anthracnose lesions. The DNAs from a variety of Colletotrichum isolates producing typical and atypical lesions, respectively, were amplified by PCR with C.gloeosporioides-specific primers. All isolates from typical anthracnose lesions yielded a 450 bp PCR product, but DNAs from isolates with atypical lesions failed to produce an amplification product. For further characterization, the rDNA 5.8S-ITS region was amplified by PCR and processed for sequencing and RFLP analysis, respectively, to verify the identity of the papaya anthracnose pathogens. The results revealed unequivocally the existence of two Colletotrichum species causing anthracnose lesions on papaya fruits: C. gloeosporioides and C. capsici. PCR-RFLP using the restriction endonuclease MspI reliably reproduced restriction patterns specific for C. capsici or C. gloeosporioides. The generation of RFLP patterns by MspI (or AluI or RsaI) is a rapid, accurate, and unequivocal method for the detection and differentiation of these two Colletotrichum species.