Strimagdo: Diploid and Tetraploid Oat Transcriptome Interactions In a Synthetic Hexaploid Oat

The genomic origins of the natural hexaploid oat Avena sativa are still uncertain.  However, it is certain that the evolution of hexaploid oats, whether through allopolyploidy (merging of different oat genomes) or autopolyploidy (duplication of existing oat genomes) or a combination of both, required the existence of two genomes (tetraploid) prior to addition of another genome (diploid) in a common nucleus. The advantage of an additional genome had to be immediate for this new species to survive and this advantage had to be a product of altered “tetraploid” gene expression. In this study, we compared transcriptomes of diploid oat, tetraploid oat and a merged diploid/tetraploid in a synthetic hexaploid oat to elucidate genome interactions and alterations to gene expression.  Briefly, a synthetic hexaploid oat, A_sA_sCCDD_m (2n=42), was previously generated by hybridization of Avena strigosa diploid oat, A_sA_s(2n=14), and Avena magna tetraploid oat, CCDD_m (2n=28), in Gideon Ladizinsky's oat genetics program.  RNA was extracted from immature seed embryos and each transcriptome was assembled de novo using RNA-Seq. We will discuss gene expression, gene silencing and derepression, and present possible underlying mechanisms of this phenomenon.