Phylogeny and systematics of the Lactucinae (Asteraceae) focusing on their SW Asian centre of diversity

Abstract

This study provides the first comprehensive molecular phylogenetic reconstruction of the lettuce alliance (Cichorieae subtribe Lactucinae of the sunflower family) in its SW Asia centre of diversity and assumed area of origin. The sampling contains multiple samples of all SW Asian Lactucinae except four unavailable rare taxa. One nuclear ribosomal and five plastid DNA markers were used for the reconstruction with maximum parsimony, maximum likelihood and Bayesian inference. A total of 716 individual sequences belonging to 56 taxa were newly generated. The nrDNA and plastid DNA gene trees show several hard topological incongruences at various levels of the trees, which make it very likely that the evolution of the subtribe was shaped by events of ancient and more recent reticulation, chloroplast capture and incomplete lineage sorting. The taxonomic conclusions from the phylogenetic analysis are drawn, and a revised inventory of the subtribe in SW Asia including new combinations and synonymies are provided.