Parallels between artificial selection in temperate maize and natural selection in the cold-adapted crop-wild relative Tripsacum

The direct progenitor of maize, teosinte, is indigenous to a relatively small range of tropical and sub-tropical latitudes. In contrast, domesticated maize thrives in temperate climates around the world as a result of artificial selection for adaption to these regions. Tripsacum, a sister genus to maize and teosinte, is naturally endemic to almost all areas in the western hemisphere where maize is cultivated. A full-length reference transcriptome for tripsacum generated using long-read isoseq data was used to characterize independent adaptation to temperate climates in these taxa, as well as the shared and lineage specific consequences of whole genome duplicate which occurred in the common ancestor of these taxa. Genes related to phospholipid biosynthesis were enriched among those genes experiencing more rapid rates of protein sequence evolution in tripsacum than in other grass lineages. In contrast with previous studies of genes under parallel selection during domestication, we find that there is a statistically significant overlap in the genes which were targets of artificial selection during the adaptation of maize to temperate climates and were targets of natural selection in temperate adapted tripsacum. The overlap between the targets of natural and artificial selection suggests genetic changes in crop-wild relatives associated with adaptation to new environments may be useful guides for identifying genetic targets for breeding efforts aimed at adapting crops to a changing climate.