Development, Validation and Characterization of Genic Microsatellite Markers in Urochloa Species

Abstract

Urochloa (syn. Brachiaria) cultivars represent 85% of tropical pastures occupying 114 million hectares of cultivated grasslands in Brazil. Despite the commercial importance of the Urochloa species, low molecular information is available and is far from saturating the genome. Investigating and obtaining more markers associated to characteristics of difficult and late expression can benefit in accelerating breeding programs of more important species. Aiming to increase the number of molecular markers, genic microsatellite markers were obtained from transcriptome of U. decumbens and analyzed for their cross-amplification to U. brizantha, U. humidicola and U. ruziziensis. Genic microsatellite markers were isolated from a transcriptome obtained of U. decumbens “Basilisk” roots. Specific primers were designed for one hundred loci, and 32 were polymorphic presenting polymorphism informative content values ranging of 0.12 to 0.81 (mean 0.54). Amplified microsatellite regions yield an average of 4.44 alleles per locus (ranging of 1 to 13). Cross-amplification to U. brizantha, U. humidicola and U. ruziziensis were successfully performed, although the number of the loci transferred varied among them. Multiple Correspondence Analysis revealed three distinct groups separating accessions and species. Four genetic markers presented high potential to distinguish sexual and apomictic accessions of Urochloa and must be further investigated. The genic markers identified in this study are the first set of expressed sequence tagged molecular markers for Urochloa species.