Plant Diversity:
Abstract
The genus Boechera (Brassicaceae) serves as a model system for studying apomictic reproduction and ecological adaptations, with most species occurring in North America. The rare occurrence of Boechera species outside their typical range provides unique opportunities to investigate genome evolution in extralimital environments. One such species, B. calcarea, has been described from the Chandalaz Mountains in northeastern Asia (Russia). This study aimed to investigate the genome structure and evolutionary history of B. calcarea. However, our analyses reveal that the species does not belong to Boechera. Instead, an integrative approach combining cytogenetic, phylogenetic and repeatome analysis identified the species as a member of one of more ancestral clades in the tribe Arabideae. The diploid Parryodes calcarea (2n = 16) exhibits Arabideae-specific chromosomal signatures, including multiple centromere repositionings. These findings clarify the misclassification of P. calcarea as Boechera, leaving Boechera falcata and Borodinia macrophylla as the only representatives of the Boechereae in the Old World. This study highlights the importance of an integrative approach in resolving taxonomic ambiguities and provides new insights into the diversification of the largest cruciferous tribe, the Arabideae.