INVESTIGATIONS OF THE GENETIC AND EPIGENETIC CHANGES IN INDUCED POLYSOMIC POLYPLOIDS OF CROP PLANTS

Most plant species are either polyploid or have experienced polyploidization during their evolution. This indicates that polyploidy generally confers a selective advantage. Doubling the chromosome number represents a "genomic shock" that can modify the structure and expression of the genome. The project "Investigations of the genetic and epigenetic changes in induced polysomic polyploids of crop plants", funded by MiUR, is aimed at gathering new information on genetic, epigenetic and metabolomic consequences of autopolyploidization in important crop species: potato (Solanum spp.), alfalfa (Medicago sativa) and birdsfoot trefoil (Lotus spp.). Research is being carried out in tetraploid genotypes obtained from diploid parents through either somatic or sexual polyploidization involving 2n gametes. Based on the results obtained in a previous study, gene expression changes induced by polyploidization is investigated using the Combimatrix microarray platform. Microarray expression data will then be validated by RT-qPCR and jointly analyzed to identify metabolic pathways affected by ploidy changes. In addition, the cytosine methylation-demethylation patterns of the genomes is being analyzed, and enzymes responsible for DNA methylation status are studied. A specific study is carried out on the flavonoid pathway due to their functional role in human and animal nutrition and forage quality. Transcriptomic analyses will reveal whether the biosynthetic genes and the transcription factors regulating the pathway are affected by polyploidization. The results obtained so far and the organization of the whole project are presented.