Novel lineage-specific inversion and legume plastome evolution

Complete legume chloroplast genomes are only available for one Papilionoid clade, and information from other lineages is thus needed to better understand this family’s atypical evolution. Martin et al. sequence the plastome of Lupinus luteus, representing the Genistoid lineage, and perform comparative analyses at the structural and sequence levels. They discover a 36-kb inversion, embedded within the already known 50-kb inversion in the large single-copy region of the Papilionoideae. This inversion occurs at the base or soon after the Genistoid emergence, and most likely resulted from a flip-flop recombination. Mutational hotspots are also identified and new potentially informative regions for phylogenetic and molecular evolutionary studies in legumes are detected.