Endophytic species of Colletotrichum associated with cashew tree in northeastern Brazil

Authors: RAMOS, DIANA - Federal Rural University Of Pernambuco; AMARAL, ANN - Federal Rural University Of Pernambuco; DUARTE, INGRID - Federal Rural University Of Pernambuco; SILVA, ANTHONY - Federal Rural University Of Pernambuco; VIEIRA, WILLIE - University Of Brasilia; Castlebury, Lisa; CAMARA, MARCOS - Federal Rural University Of Pernambuco

Submitted to: Fungal Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2024
Publication Date: 4/11/2024
Citation: Ramos, D.G., Amaral, A.G., Duarte, I.G., Silva, A.C., Vieira, W.A., Castlebury, L.A., Camara, M.P. 2024. Endophytic species of Colletotrichum associated with cashew tree in northeastern Brazil. Fungal Biology. 128(3):1780-1789. https://doi.org/10.1016/j.funbio.2024.04.002.
DOI: https://doi.org/10.1016/j.funbio.2024.04.002

Interpretive Summary: Anthracnose is a severe disease caused by species of the genus Colletotrichum and characterized by lesions on leaf tissue. It is one of the most severe and widely distributed cashew diseases occurring in Brazil. Colletotrichum species are commonly found as pathogens or asymptomatically associated species, and occasionally on dead tissue of a wide range of hosts. The fungal species associated with cashew trees are poorly studied. In this study, fungal species related to the anthracnose disease pathogens were studied and identified. Six species were identified, and all were capable of causing disease under certain conditions. This information will be useful to plant pathologists and other researchers seeking to understand the disease process and management in cashew.

Technical Abstract: Anthracnose caused by species of the genus Colletotrichum is the most severe and widely distributed cashew disease occurring in Brazil. Colletotrichum species are commonly found as pathogens, endophytes, and occasionally saprophytes in a wide range of hosts. The endophytic species associated with cashew trees are poorly studied. In this study, we report the Colletotrichum endophytic species associated with cashew trees in the state of Pernambuco, their prevalence in different plant organs (leaves, veins, branches and inflorescences) in two areas of the urban area of Recife-PE, and compare the species in terms of pathogenicity and aggressiveness using different inoculation methods (wounded × unwounded). Six species of Colletotrichum were identified according to multilocus phylogenetic analyses, including C. asianum, C. chrysophilum, C. karsti, C. siamense, C. theobromicola, C. tropicale, in healthy cashew tree tissues. There were differences in the percentage of isolation in relation to the prevalence of colonized tissues and collected areas. C. tropicale was the most prevalent species in both geographic areas and plant tissues collected. There was no pattern of distribution of species among geographic areas and plant tissues. All isolates were pathogenic in injured tissues of cashew plants. We found that the best method to test the pathogenicity of Colletotrichum species is the combination of leaves, presence of wounds, and conidial suspension, as these better represent the natural infection process. C. siamense was more aggressive than all other species.