Abstract

GARCIA-BASTIDAS, Nevar; GUTIERREZ-SANCHEZ, Pablo  and  MARIN-MONTOYA, Mauricio. Development of mitochodrial and microsatellite markers for the study of genetic variation of Spongospora subterranea f. sp. subterranea. Bioagro [online]. 2013, vol.25, n.2, pp.91-100. ISSN 1316-3361.

Spongospora subterranea f. sp. subterranea (Sss), the causal agent of powdery scab disease, is one of the most limiting pathogens of potato causing significant damage in both roots and tubers. In spite of being an obligate pathogen, Sss can remain dormant in soils in the form of cystosori. Currently, there is neither effective chemical treatment for Sss nor commercial resistant varieties of potato. The best strategy for controlling Sss consists in the use of certified tuber-seed in cystosori-free soils. It is very important to obtain Sss-resistant plants, a strategy that requires knowledge of the population structure and genetic diversity of the pathogen. In this study, the presence of microsatellite regions was investigated by partial genome pyrosequencing of Sss; specific primers for amplifying these potential markers were designed. Additional primers targeting mitochondrial DNA were designed as tools for Sss detection and variation studies. After evaluation of specifity and variability among strains of the three types of Sss, five primer pairs amplifying microsatellites with motives AC, TGA, TGTC, GGTC and CCGTGC, with varying repeats were chosen. Similarly, three primer pairs targeting the mitochondrial DNA resulted in amplicons with variation levels of 4-9 % in the tested Sss isolates. These results will be useful in future population studies of Sss aimed to support both genetic improvement and tuber-seed certification programs.

Keywords : PCR; powdery scab; single sequence repeats; Solanum tuberosum.

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