Plastid marker-based phylogeny reveals insights into relationships among Papilionoideae species

Abstract

Abstract The Papilionoideae subfamily comprises more than 14,000 species, 501 genera and 32 tribes, representing two-thirds of all genera and species in the Fabaceae family. Papillonoids are recognized for their food and forage importance, wide distribution in different biomes and variation in floral architecture as well as plastome structure. Due to the high-level conservation of chloroplast genomes, when compared to nuclear and mitochondrial genomes, phylogenetic analysis based on chloroplast DNA (cpDNA) have been elucidating the relationships among the main Papilionoideae's taxon. However, the phylogeny of some clades of the subfamily remains unresolved. Aiming at the phylogenetic reconstruction of the deep branching species of Papilionoideae, concatenated sequences of six loci (matK, psaA, psbA, psbD, rbcL and rpoC2) of cpDNA from 117 species of Papilionoideae were analyzed using the maximum likelihood methodology. The plastomes of Papilionoideae showed low conservation and similarity. Phylogenetic analysis resulted in a monophyletic tree, confirming the division of the subfamily into four main clades (NPAAA, ADA, Genistoids and Dalbergioids). The sibling group relationship of the ADA clade with the Genistoids clade was demonstrated, with high support. The paraphyly of the Phaseoleae and Millettiae tribes was evidenced within the NPAAA clade with unresolved phylogeny of the Genistoids clade. As well, was observed that only species of the ADA clade have no rhizobium nodules, which may be a possible synapomorphy to support the relationships of this group. The analysis also suggest that the main Papilionoideae clades diverged from the Paleocene onwards.