Anatomical and physiological specializations for plant adaptation to harsh climates result from molecular mechanisms that can be encoded in the nucleus or organelle. In this study, the complete plastomes of an arctic species, Oxytropis arctobia Bunge (Fabaceae), and a closely related temperate species, O. splendens Douglas ex Hook., were assembled, annotated, and analyzed to identify differences that might help explain their adaptation to different environments. This is consistent with the previously sequenced O. bicolor DC. and O. glabra plastomes, O. arctobia and O. splendens plastomes both have the common features of the inverted repeat-lacking clade (IRLC), as well as atpF intron loss, which is unique to the genus. However, significant differences were observed between the plastomes of O. arctobia and O. splendens and other closely related species (Oxytropis spp. and Astragalus spp.), including a 3 kb inversion, two large insertions (>1 kb), significant modifications of the accD gene, and an overall larger size.
Keywords: Fabaceae; IRLC group; Oxytropis; arctic plants; fabacées; groupe IRLC; génome plastidique; plantes arctiques; plastid genome.