Phenotypic, metabolic and genetic consequences of polyploidization in Solanum species

In the literature there is scant information on the effects imposed by polyploidization. Polyploids often show novel phenotypes that are not present in their diploid progenitors or exceed the range of the contributing species. Some of these traits could play a role in the increased heterosis or, more in general, could allow polyploids to enter new ecological niches. Shedding new light on the effect of polyploidization would be particularly important in that this would allow: 1) to perform evolutionistic considerations (Hegarty and Hiscock, 2008); 2) to study the plasticity of plant genomes (Leitch and Leitch, 2008); and 3) to interpret metabolomic and proteomic changes associated to polyploidy (Seoighe and Gehring, 2004). Moreover, since polyploidization is often used in plant breeding to produce genetic variability and to overcome sexual barriers, knowledge on the characteristics of newly generated polyploids is crucial for an efficient selection of plant materials (Carputo et al. 2003). The main aim of this thesis is to study the complex changes associated to autopolyploidization in potato. In particular, specific goals are to produce 4x genotypes from two 2x wild species, S. commersonii and S. bulbocastanum, and to explore phenotypic, genetic, epigenetic, and metabolomic alterations in synthetic tetraploids in comparison with diploid species.