Resumo

PINZON GUTIERREZ, Yeimy Alexandra; BUSTAMANTE, Silvia Lizette  e  BUITRAGO HURTADO, Gustavo. Differential molecular diagnosis Colletotrichum gloeosporioides and Fusarium oxysporum in yam (Dioscorea sp.). Rev. colomb. biotecnol [online]. 2013, vol.15, n.1, pp.52-60. ISSN 0123-3475.

Fungal diseases are responsible for the greatest losses in the Colombian yam crop, among these the anthracnose stands out as the most devastating. In recent years, fungi with low prevalence but high spread power such as F. oxysporum have expanded its presence in yam crops favoring the development of rot disease. Despite the importance of yam crop on the Colombian Caribbean Coast, the Pacific and the Amazon, this is considered an orphan crop because are few efforts made in its investigation in the world and particularly in Colombia. In order to contribute to the correct and timely diagnosis of fitopathogens that affect the yam crop, this study obtained fungal isolates from leaves with necrotic spots. Of these isolates, five showed morphological characteristics of Colletotrichum and three of Fusarium genus. The species identity was determined by ITS secuencing, corresponding to Colletotrichum gloeosporioides and Fusarium oxysporum. The evaluation of molecular markers for differential and simultaneous detection of these pathogens allowed to choose the elongation factor alpha (EF-α) as the best diagnostic test. Pathogenicity test confirmed the capacity of C. gloeosporioides to cause anthracnose symptomatology in leaves and F. oxysporum isolates to trigger rot in tuber, whose presence in leaves could been associated to its easy and fast conidial spread, to its heightened incidence in soil which is its natural habitat, and its prolonged survival.

Palavras-chave : yam; Colletotrichum gloeosporioides; Fusarium oxysporum; elongation factor alpha (EF-α); anthracnose; rot.

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