Resolving the evolutionary history of Leucaena using Chloroplast and Mitochondrial Transcriptome Data

The complex evolutionary history of the mimosoid legume genus Leucaena includes diploid and tetraploid speciation events that have been influenced by human translocation. A full understanding of the patterns of divergent and reticulate evolution in Leucaena requires phylogenetic resolution from nuclear and organellar markers. However, sequences from a handful of cpDNA genes, as representatives of organellar genomes, have only provided modest phylogenetic resolution. Here we use de novo assembled transcriptome data to obtain sequences from chloroplast and mitochondrial expressed genes to further explore patterns of divergent and reticulate evolution in Leucaena. The cpRNA and mtRNA derived trees identified well-supported lineages that are congruent with previously recognized major clades, but with greater resolution and support therein. With the exception of L. confertiflora, the inferred maternal origin for each allotetraploid species was consistent with previous results. These data will provide the critical phylogenetic resolution required for future evolutionary investigations focused on patterns of diversification among the genes and genomes of Leucaena.