Fungal diversity and Fusarium oxysporum pathogenicity associated with coffee corky-root disease in Mexico
Lopez-Lima D., Carrion G., Sanchez-Nava P., Desgarennes D., Villain L.. 2020. Revista de la Facultad de Ciencias Agrarias. Universidad Nacional de Cuyo, 52 (1) : p. 276-292.
The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia in corky-root samples in contrast with absence of every fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonize the vascular system of coffee plants although none caused wilting symptoms.
Mots-clés : coffea; fusarium oxysporum; agent pathogène; mexique
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Agents Cirad, auteurs de cette publication :
- Villain Luc — Bios / UMR DIADE