Genomic analyses of arugula (Eruca sativa) accessions reveal domestication history and breeding insights

Abstract Eruca sativa , or arugula, a leafy vegetable from the Mediterranean region, is gaining popularity worldwide. However, its domestication history and genetic diversity remain poorly understood. This study investigates the genetic background of globally collected arugula accessions, their domestication history, and the implications for future breeding strategies. Among the 202 arugula accessions analysed, four distinct groups were identified. Group 1 (G1) appears to be misidentified as arugula and is more closely related to radish ( Raphanus sativus ) and Brassica spp. Group 2 (G2), Group 3 (G3), and Group 4 (G4) likely represent arugula populations evolved separately, with G4 showing greater genetic isolation and drifts. Geographically, G2 accessions cluster in Europe, G3 in North Africa, and G4 in South Asia (furthest from the Mediterranean region). Phylogenetic and demographic history analyses suggest that G2 is more ancient than G3 and G4. While G3 and G4 share a more recent common ancestor, small scale introgression between G2 and G3 was detected. Selective sweeps signatures revealed 12 genes under positive selection in G4 compared to G2, and these 12 genes are likely associated with adaptive divergency, suggesting that arugula has not undergone stringent artificial selection. A potential hybrid zone between Turkey, Israel, and Iran was identified. Accessions from this zone may serve as a valuable resource for screening new arugula varieties with superior traits. Although 202 accessions were studied, some exhibited high genetic similarity. To enhance germplasm diversity for breeding, future efforts should prioritize expanding collections in regions where arugula has naturalized.