title: Short-term hybridisation activates Tnt1 and Tto1 Copia retrotransposons in wild tuber-bearing Solanum species.
abstract: Interspecific hybridisation in tuber-bearing species of Solanum is a common phenomenon and represents an important source of variability, crucial for adaptation and speciation of potato species. In this regard, the effects of interspecific hybridisation on retrotransposon families present in the genomes, and their consequent effects on generation of genetic variability in wild tuber-bearing Solanum species, are poorly characterised. The aim of this study was to analyse 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, with specific primers for Tnt1 and Tto1 retrotransposon families (Order LTR, Superfamily Copia). The results indicate that at morphological level, interspecific hybrid genotypes differ from their parental species, whereas derived intraspecific hybrids do not. In both cases, we observed significant reductions in pollen grain viability, and a negative correlation with Tnt1 mobility. Both retrotransposons, Tto1 and Tnt1, were mobilised in the genotypes analysed, 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 compared with the parental genotypes. These patterns were positively correlated with the activity of the retrotransposons. The results suggest a possible mechanism through which hybridisation events generate genetic variability in tuber-bearing species of Solanum through retrotranposon activation.
authors.affiliation: Dpto. de Biología, Grupo INTERBIODES (Biological Interactions of Desert), CIGEOBIO (FCEFyN, UNSJ/CONICET), Rivadavia, San Juan, Argentina.
authors.forename: R C
authors.initials: RC
authors.lastname: Paz
authors.affiliation: Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina.
authors.forename: A P
authors.initials: AP
authors.lastname: Rendina González
authors.affiliation: Laboratorio de Biología Molecular, Instituto de Biología Agrícola de Mendoza (IBAM), Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Chacras de Coria, Mendoza, Argentina.
authors.forename: M S
authors.initials: MS
authors.lastname: Ferrer
authors.affiliation: Laboratorio de Biología Molecular, Instituto de Biología Agrícola de Mendoza (IBAM), Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Chacras de Coria, Mendoza, Argentina.|Instituto Nacional de Tecnología Agropecuaria (INTA), La Consulta, San Carlos, Mendoza, Argentina.
authors.forename: R W
authors.initials: RW
authors.lastname: Masuelli
mesh_terms: D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics*; D006824:Hybridization, Genetic; D008969:Molecular Sequence Data; D035281:Plant Tubers / Q000235:genetics; D018626:Retroelements / Q000235:genetics*; D017422:Sequence Analysis, DNA; D032322:Solanum / Q000235:genetics*; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D018626:Retroelements
keywords: Genomic shock; hybridisation; pollen viability; retrotransposon activation; sequence-specific amplification polymorphism; transposon methylation display; tuber-bearing Solanum spp