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

Abstract

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. Key words: Brassicaceae, dispersal pattern, eastern Asia, phylogenetic relationship, Qinghai-Tibet Plateau (QTP). (Al-Shehbaz, 2011). As a major biodiversity hotspot, with approximately 180 species of Brassicaceae in 76 genera, the Dispersal of Brassicaceae around QTP 203 www.jse.ac.cn

Resolving robust phylogenetic relationships of core Brassicaceae using genome skimming data

“…Our nrDNA phylogeny recovered four monophyletic clades (namely clades a, b, c, and d) in which the intratribal relationships were generally highly supported. Interestingly, the unsolved tribe Megacarpaeeae in target captured analysis (Huang et al, 2015; Nikolov et al, 2019) was well resolved as sister to the subclade comprising Stevenieae and Arabideae (BIPP = 1.0) here, which was congruent with the ITS phylogeny by Qian et al (2018). Our results indicated that the full‐length nrDNA cistron sequences might contain abundant phylogenetic informative sites and have the potential to improve relationships at intratribal and lower taxonomic ranks of core Brassicaceae.…”

“…As indicated in Fig. 3, the most remarkably incongruent relationships were those involving the LII, which consisted of only four tribes initially (Zhao et al, 2010; Franzke et al, 2011; Huang et al, 2015; Qian et al, 2018; Nikolov et al, 2019). Controversial results from previous studies were generally attributed to homoplasy in morphology (e.g., Al‐Shehbaz et al, 2006; Beilstein et al, 2006; Al‐Shehbaz, 2012).…”

The chloroplast genome of Farsetia hamiltonii Royle, phylogenetic analysis, and comparative study with other members of Clade C of Brassicaceae

“…Intergenic spacer (IGS) regions exhibited the highest average nucleotide diversity, followed by intronic and coding regions. The finding that protein-coding genes have little nucleotide diversity supports the assumption that they are more conserved in Brassicaceae species [3,12,22,93,94]. Nucleotide diversity varies from 0.00085 to 0.08516; such low nucleotide diversity values indicate plastome structure conservation in clade C members, and a lower rate of nucleotide diversity has been seen in numerous other plants [95][96][97][98].…”

Phylogenomic and Macroevolutionary Evidence for an Explosive Radiation of a Plant Genus in the Miocene

“…The estimate of net diversification rates between 11.8 and 8 Ma is 1.03 species per million years (species/Myr). This rate is higher than in many documented examples of fast plant radiations in Southwest China, including of alpine bamboos (0.75 species/Myr; Poaceae; Ye et al 2019), tribe Anastaticeae (0.17 species/Myr; Brassicaceae; Qian et al 2018 ), Hirculoideae and Kabschia (0.455 and 0.471 species/Myr; Saxifragaceae; Ebersbach et al 2017 ), and 17 angiosperm clades (ca. 0.12 species/Myr; Xing and Ree 2017 ); or in other biodiversity hotpots; for example, Fosterella within the Andean Mountains (0.40 species/Myr; Bromeliaceae; Wagner et al 2013 ).…”