CONICET | Buscador de Institutos y Recursos Humanos

Interspecific hybridization in tuber-bearing species of Solanum is a common phenomenon and represents an important source of variability, crucial for adaptation and speciation of the potato species. In this regard, the effects of interspecific hybridization on retrotransposons families present in the genomes, and their consequent effects on the generation of genetic variability in wild tuber bearing Solanum species, are poorly characterized. The aim of this study was to analyze the activity of retrotransposons in inter and intraspecific hybrids between S. kurtzianum and S. microdontum, obtained by controlled crosses and the effects on morphological, genetic and epigenetic variability. For genetic and epigenetic analysis, S-SAP (Sequence-Specific Amplification Polymorphism) and TMD (Transposon Methylation Display) techniques were used respectively, using specific primers for Tnt1 and Tto1 retrotransposons families (Order LTR, Superfamily Copia). The results indicate that at the morphological level, interspecific hybrid genotypes differ from their parental species, whereas deriving intraspecific hybrids do not. In both cases, we observed significant reductions in pollen grains viability, and a negative correlation with Tnt1 mobility. Both retrotransposons, Tto1 and Tnt1, mobilized in the genotypes analyzed, with mobility ranging from 0 to 7.8%. Furthermore, at the epigenetic level, demethylation was detected in the vicinity of Tnt1 and Tto1 in the hybrids, in comparison with the parental genotypes. These patterns were positively correlated with the activity of the retrotransposons. These results suggest a possible mechanism by which hybridization events, generate genetic variability in tuber-bearing species of Solanum through retrotranposons activation.