High quality genome sequence reveals important events during domestication of White Lupin
Résumé
White lupin (Lupinus albus; 2n=50) is the only crop producing cluster roots, an outstanding developmental adaptation to low phosphate soils. We report a high-quality chromosome-scale assembly of white lupin genome, together with an extensive transcriptome data from ten different organs. We used singlemolecule real-time technology, in combination with short-reads sequencing and optical and genetic maps to have a successful assembly. The final assembly size is 443 Mb with a N50 of 17 Mb. About 98% of the assembled genome is included on the 25 pseudo-chromosomes. The structural annotation identified 38258 coding genes and 3,129 ncRNA, being 97.3% genes anchored on the pseudo-chromosomes. Genome of white lupin is laden with gene duplications and repetitive elements, which represent ~55% of the genome. A comparative evolutionary analysis of white lupin with other legumes revealed that it experienced a whole genome triplication in about 10 M years ago. We resequenced other 15 white lupin accessions, including a landrace and a non-domesticated variety. This has shown a highly polymorphic genome that has been impacted by domestication in different ways. Some transposons families present on the non-domesticated variety have disappeared in modern accessions, as well as the protein content of the seed has changed. Interestingly, the domestication has also modified cluster root formation. The cluster roots are formed earlier on time and closer to topsoil in the cultivated varieties. Altogether, this genome is a valuable resource and represents a keystone for legume genomics research.