A genomic and functional framework for the rapid domestication of the wild plant Chenopodium album

Global reliance on a small number of genetically uniform crops makes our food system increasingly vulnerable to pests, diseases, and climate change, highlighting the need to develop resilient local species as crops. Chenopodium album, a stress-tolerant, protein-rich wild plant whose seeds were part of prehistoric Northern European diets and whose leaves are still foraged worldwide, remains undomesticated despite its agrifood potential. We established a Danish collection of 143 accessions and combined seed metabolomics, ploidy assessment and genomics to uncover the molecular basis of key nutritional and anti-nutritional traits. Seed profiling revealed substantial variation in protein content (14-22%), comparable to or higher than major crops, and 16 distinct triterpenoid saponins, which are widespread bitter and anti-nutritional compounds. Seed production of field-grown lines reached up to 1.5 t/ha in trials conducted in Denmark, demonstrating promising yield potential. A high-quality tetraploid genome of a low-saponin line was assembled and contrasted with resequencing of a diploid high-saponin line in order to uncover the genetic basis of saponin variation in C. album. Comparative genomic, phylogenetic, and transcriptomic analyses identified structural variants and candidate genes associated with saponin biosynthesis, and functional validation confirmed the coordinated activity of a {beta}-amyrin synthase, three CYP716 cytochromes P450, and a glucuronosyltransferase that reconstitute the core C. album saponin pathway. Together, these results define the genomic and biochemical foundation of C. album, establishing a platform for its rapid domestication as a locally adapted, high-protein seed crop and a model for translating wild plant diversity into future food security.