You say tomato, I say potato: high-quality genome assembly of the sister-group species Solanum etuberosum provides insights into genome and trait evolution

To elucidate the evolutionary history and basis of chromosomal, molecular and phenotypic differences between tomato and potato, genomic data from a key outgroup species is needed. Solanum etuberosum, a non-tuber-bearing species from Chile, fulfills this requirement: its ancestors diverged from the tomato-potato lineage shortly before the split of the tomato and potato clades. With the aim of investigating both genome and trait evolution, we sequenced and assembled the genome of S. etuberosum. The initial Illumina assembly consisted of 3666 scaffolds with the N50 statistic of 1.7Mb and captured 94% of the predicted 702 Mb genome size. The assembly was further scaffolded using
BioNano genome mapping, yielding a final genome assembly that surpassed an N50 of 5Mb.Hence, it is one of the most contiguous Solanum genome assemblies thus far, and with 97% coverage of the expected gene space, also one of the most complete ones. We subsequently annotated the genome
sequence and reconstructed the evolution of genes crucial to potato and/or tomato phenotypes and specifically related to tuber formation, pathogen resistance, flower color and glycoalkaloid biosynthesis. The genome of S. etuberosum thus proved to be an invaluable resource for novel insights in the Solanum genus.