The impact of genome evolution on the allotetraploid Nicotiana rustica – an intriguing story of enhanced alkaloid production

Background Nicotiana rustica (Aztec tobacco), like common tobacco (Nicotiana tabacum), is an allotetraploid formed through a recent hybridization event; however, it originated from completely different progenitor species. Here, we report the comparative genome analysis of wild type N. rustica (5 Gb; 2n = 4x = 48) with its three putative diploid progenitors (2.3–3 Gb; 2n = 2x =24), Nicotiana undulata, Nicotiana paniculata and Nicotiana knightiana.