Abstract:
The Millettioid/Phaseoloid (MP) clade is one of the largest clades in the subfamily Papilionoideae, consisting of many economically important species globally distributed. Despite the eminence of previous works, many evolutionary perspectives remain unknown. Thus, this study is most elaborate by complementing the newly sequenced plastome data with the plastomes, matK and nrDNA ITS sampled from the Genebank to provide innovative insight into the molecular evolution encompassing the plastome structural variation and spatiotemporal dynamics of the MP clade. Their plastomes are typically quadripartite and have experienced independent structural variations with a few yielding phylogenetic implications. The multi-dataset generated from the plastid phylogenomics presents a well-resolved phylogenetic relationship but topologically different following the placement of Butea monosperma and Spatholobus sp. subclade. Six main lineages were identified from the reconstructed phylogenetic framework comprising 749 species of the MP clade based on the combined datasets, resolved most deep and shallow nodes, and supported the monophyly of Abreae, Desmodieae, Indigofereae and Psoraleeae tribes. In contrast, the Millettioids and Phaseoloids lineages are still nonmonophyletic, being resolved into multiple sublineages. The fossil-calibrated dating analysis showed approximately a million-year delay in the diversification of the MP clade as indicated by the phylogenetic fuse—stem node (c. 62 Ma) and crown node (c. 61 Ma)—in the Paleocene. The biogeographic analysis suggested that the MP clade originated in Africa and subsequently dispersed to Asia, Europe, Australia, and the Americas at different periods in the Cenozoic, suggesting the Paleotropical origin for the clade. There was evidence for shifts in diversification rates across the phylogeny of the MP clade throughout the Cenozoic, with a rapid increase in net diversification and speciation rates starting c. 10 Ma and continuing toward the present. Possible explanations for the present-day species richness and spatio-temporal dynamics of the MP clade lineages include boreotropical migration, frequent intra- and intercontinental long-distance dispersals throughout the Cenozoic, and elevated speciation rates following the Mid-Miocene Climatic Optimum. Together, these results provide novel insights into major diversification patterns of the MP clade, setting the stage for future evolutionary research on this vital legume lineage.
Speaker: Dr. Oyetola Oyebanji
Affiliation: University of Louisiana
Time: 4:30 PM, Wednesday, Dec. 19, 2023
Venue: Tencent Meeting ID：823-833-779
https://meeting.tencent.com/dm/HnCbrsD3y5pL
