The tobacco genome sequence
Nicotiana tabacum (common tobacco) is a major crop species and a model organism, for which only very fragmented genomic sequences have been available until recently. The three most commonly used tobacco types are flue-cured (or Virginia), Burley and Oriental, which are traditionally grown and harvested under different agricultural practices in over 120 countries. The tobacco plant stands out as a complex allotetraploid with a large 4.5 Gb genome, a significant proportion (>70%) of which is represented by repeats. As a species, N. tabacum (2n=4x=48) evolved through the interspecific hybridisation of the ancestors of Nicotiana sylvestris (2n=24, maternal donor) and Nicotiana tomentosiformis (2n=24, paternal donor) about 200,000 years ago. Considerable interest has centred on understanding the origin, organisation and evolution of the N. tabacum genome. Here we report high-quality draft genomes for three main tobacco varieties. These genomes show both the low divergence of tobacco from its ancestor genomes and display microsynteny with other Solanaceae species. We anticipate that the draft genomes will strengthen the use of N. tabacum as a versatile model organism for functional genomics and biotechnology applications.
 Sierro N, Battey JN, Ouadi S, Bakaher N, Bovet L, Willig A, Goepfert S, Peitsch MC, Ivanov NV. The tobacco genome sequence and its comparison with those of tomato and potato. Nature Communication. 2014 May 8; 5:3833. doi: 10.1038/ncomms4833. PubMed PMID: 24807620; PubMed Central PMCID: PMC4024737.