Allelic variants of linked SSR correspond with aminoacidic changes in apoplastic invertase.

SILVANA COLMAN; MASSA GABRIELA ALEJANDRA; MARTÍN CARBONI; MARTÍN CASTELLOTE; FEINGOLD SERGIO ENRIQUE

Biejing

Conferencia; 10th Solanaceae Conference (SOL2013); 2013

Association mapping is a newly adopted approach in plant QTL mapping, alternative to linkage analysis. This strategy avoids building segregating populations, increase mapping resolution and allows the analysis of virtually all alleles present in the studied genotypes. Native potatoes of South America present a more diverse genetic base than European bred potatoes and constitute an important reservoir of allelic variants of genes of interest for future breeding. Microsatellites or simple sequence repeats (SSRs) are one of the preferred markers for mapping as they are multiallelic, reproducible and amenable to automation. With the recent sequencing of the potato genome, their cost of development dropped to a minimum, as the identification of SSR motifs near or within genes of interest is performed in silico. However, the use of SSRs in association mapping requires the consideration of homoplasy, where SSR alleles are identical in size but not identical by descent. To verify this, an SSR coded in an intron of the InvGF gene (Sti002) was assayed in 49 diverse Solanum tuberosum Group Andigena from NW Argentina. Five SSR alleles were detected and the whole gene was cloned from different allele carrying genotypes and sequenced. The same SSR alleles from distinct genotypes presented the same nucleotide sequence of InvGF, whereas, different SSR alleles showed variation at both the nucleotide and aminoacidic sequences. This result validates the use of SSR in association mapping.