The unexplored diversity of wild lupins provides rich genomic resources and insights into lupin evolution

Abstract

Lupin crops provide nutritious seeds as an excellent source of dietary protein. However, extensive genomic resources are needed for the adaptation of lupin crops, particularly to improve their nutritional value and facilitate their adaptation to harsh environments caused by the changing climate. Such resources can be derived from crop wild relatives, which represent a large untapped source of genetic variation for crop improvement. Here we describe the first whole-genome sequences of the cross-compatible speciesLupinus cosentinii(Mediterranean) and its pan-Saharan wild relativeL. digitatus, which are well adapted to drought-prone environments and partially domesticated. We found that both species are tetraploids, with similar genome structures, distributions of gene duplications, and numbers of expanded and contracted gene families. The expansion and contraction of gene families that determine seed size, a paradigmatic domestication trait, indicates that gene duplication may have led to morphological adaptations inLupinus cosentiniiandL. digitatusdiffering from those inL. albus, a domesticated lupin used as a reference. Seed size may therefore reflect convergent evolution mechanisms that play a key role in lupin domestication.