Cross-pathogenicity of Colletotrichum isolates on tropical fruit species in Brazil

Abstract

Due to their perishable nature, tropical fruits are prone to pre-and post-harvest loss attributed to biotic and abiotic factors. Although the production of tropical fruits such as banana (Musa acuminata), guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), and passion fruit (Passiflora edulis) is in the increasing trend, the post-harvest loss remains a challenge for the production of excess tropical fruits worldwide. Severity and cross-pathogenicity of different Colletotrichum species attributed to the reasonable loss of such fruits, hence molecular detection and discrimination of such fungal species are indispensable for post-harvest disease management. In the present study, the rDNA ITS was used for molecular identification of fungal isolates from five tropical fruits at the post-harvesting stage. Most of the identified fungi belong to the genus Colletotrichum. Furthermore, the cross-pathogenicity and disease symptom severity of the isolates across these fruit samples was also investigated. The result showed that most isolates are host-specific, passion fruit being the ideal host for all the discriminated isolates. The symptoms caused by Colletotrichum isolates showed similar patterns as revealed by lesion diameter analysis. The work provided important data on the cross-pathogenicity and disease symptom characteristics of Colletotrichum pathogens known to affect the five tropical fruits investigated.