Main content area

Phylogenetics and dispersal patterns of Brassicaceae around the Qinghai–Tibet Plateau

Qian, Chaoju, Shi, Yong, Liu, Yuan, Yan, Xia, Ma, Xiao‐Fei
Journal of systematics and evolution 2018 v.56 no.3 pp. 202-217
Draba, Lepidium appelianum, chloroplast DNA, internal transcribed spacers, monophyly, statistical analysis, trees, China
Brassicaceae, one of the most diverse and economically valuable plant families, is distributed all over the world. Previous studies have suggested that Brassicaceae originated and diversified in the Old World. In this study, the phylogenetic relationships of 17 tribes of Brassicaceae from the Qinghai–Tibet Plateau (QTP) and adjacent areas were investigated using nuclear ribosomal internal transcribed spacer (nrITS) and chloroplast DNA sequence data (rbcL and petB‐petD) with maximum likelihood, maximum parsimony, and Bayesian methods. As suggested by both the nrITS and chloroplast DNA trees, Cardaria pubescens (C.A.Mey.) Jarm. (Lepidieae) and Draba lanceolata Royle (Arabideae) should be classified in the Eutremeae and Cardamineae, respectively. Based on over 700 newly sequenced and published nrITS sequences of Brassicaceae, an up‐to‐date comprehensive phylogeny of the family was reconstructed using the maximum likelihood method. In the phylogenetic tree, 10 monophyletic tribes were detected. They were used to clarify the lineage diversification and dispersal patterns of the 10 tribes. The results showed that most of the monophyletic tribes may have originated in different regions of the world, and then dispersed into other regions surrounding the QTP. Rapid lineage diversification rate shifts were detected in several tribes, such as Anastaticeae, which experienced a rapid shift event ∼1.38 Mya, corresponding to the rapid uplift of the QTP, indicating that the recent uplift of the QTP could have promoted diversification in Brassicaceae across and adjacent to the QTP.