Abstract

OSORIO-GIRALDO, Inés et al. Genetic variability of Spongospora subterranea f. sp. subterranea in Colombia. Bioagro [online]. 2012, vol.24, n.3, pp.151-162. ISSN 1316-3361.

Powdery scab (Spongospora subterranea f. sp. subterranea - Sss) is one of the most important re-emerging diseases of potato crops in Colombia. Sss can cause severe root damage and compromise the quality of tubers. Moreover, Sss zoospores can also serve as vector of Potato mop-top virus (PMTV, Pomovirus). Sss can survive in the soil for decades due to the formation of resistance structures or cystosori. For this reason, the disease can only be efficiently controlled by using resistant potato varieties and certified seed tubers. In this work, the level of variation of 127 Sss isolates from the Colombian provinces of Antioquia, Boyacá, Cundinamarca and Nariño was evaluated. This information is of great value for genetic improvement programs of potato and can also be used in the design of asymptomatic detection tests. Cluster analysis of ITS rDNA sequences revealed the existence of three Sss variants. Types I and II have been reported in other countries while type III has only been found in Colombia. This information was used to design a PCR-RFLP test to discriminate the pathogen´s ribotypes.

Keywords : rDNA; ITS; PCR; Powdery scab; Solanum tuberosum.

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