Molecular phylogeny and systematics of the tribe Chorisporeae (Brassicaceae)

Abstract

Sequence data from nuclear (ITS) and chloroplast (trnL-F) regions for 89 accessions representing 56 out of 64 species from all five genera of the tribe Chorisporeae (plus Dontostemon tibeticus) have been studied to test the monophyly of the tribe and its component genera, clarify its boundaries, and elucidate its phylogenetic position in the family. Both data sets showed strong support for the monophyly of the Chorisporeae as currently delimited, though the position of its tentative member D. tibeticus was not resolved by ITS. Parrya and Pseudoclausia are polyand paraphyletic with regard to each other, and Chorispora is either polyphyletic or at least paraphyletic (comprising Diptychocarpus) within a weakly supported monophyletic clade. The incongruence in branching pattern among the markers was most likely caused by hybridization and possibly influenced by incomplete lineage sorting. The present results suggest uniting Pseudoclausia, Clausia podlechii, and Achoriphragma with Parrya and transferring P. beketovii and P. saposhnikovii to Leiospora (Euclidieae). We also obtained support for splitting Chorispora into two geographically defined groups, one of which is closer to Diptychocarpus. Both data sets revealed a close relationship of the Chorisporeae to Dontostemoneae, while ITS also indicated affinity to Hesperideae. Therefore, the position of Chorisporeae needs further verification.

Monophyletic Origin and Evolution of the Largest Crucifer Genomes

“…5The genome structures described here and the inferred ancestral genome (CEK) point to a monophyletic origin of the clade. (6) Phylogenetic analyses based on nuclear and chloroplast gene markers repeatedly retrieved the Hesperis clade as being a monophyletic lineage (Beilstein et al, 2006(Beilstein et al, , 2008(Beilstein et al, , 2010German et al, 2009German et al, , 2011Couvreur et al, 2010;Warwick et al, 2010;Huang et al, 2016;Guo et al, 2017; this study).…”

“…According to the most recent tribal treatment of Brassicaceae (Al-Shehbaz, 2012), lineage III (Beilstein et al, 2006) or clade E (Huang et al, 2016) includes seven tribes, namely Anastaticeae (ANAS; 13 genera/ 65 species), Anchonieae (ANCH; 10/75), Buniadeae (BUNI; one/two), Chorisporeae (CHOR; four/55), Dontostemoneae (DONT; two/17), Euclidieae (EUCL; 28/149), and Hesperideae (HESP; two/52), plus the recently described monotypic Shehbazieae (SHEH; one/one; German and Friesen, 2014). In congruence with some previous studies (for review, see German et al, 2011), this circumscription of lineage III was not fully supported by the multigene analysis of Huang et al (2016), due to ANAS (Lobularia maritima) being positioned outside of the monophyletic clade E or Hesperis clade of six tribes (ANCH, BUNI, CHOR, DONT, EUCL, and HESP; SHEH was not studied but should be assigned here because it represents an ancient hybrid between CHOR and DONT). ANAS consistently clustered with representatives of Biscutelleae, Cochlearieae, and Iberideae, as a newly recognized clade C (Huang et al, 2016;Guo et al, 2017).…”

Molecular phylogeny of Menonvillea and recognition of the new genus Aimara (Brassicaceae: Cremolobeae)

“…Since the monophyly and phylogenetic relationships within Menonvillea remained unresolved, it is important to study the molecular phylogeny of the genus using both nuclear and chloroplast data. Sequences from ITS and the trnL-F region were shown to be useful in evaluating relationships among Brassicaceae, particularly at the generic level (e.g., Koch & Mummenhoff, 2001;Warwick & al., 2002Warwick & al., , 2006Warwick & al., , 2007Warwick & al., , 2008Warwick & al., , 2009Warwick & al., , 2010Warwick & al., , 2011O'Kane & Al-Shehbaz, 2003;Bailey & al., 2006;Alexander & al., 2010;Moazzeni & al., 2010;German & al., 2011).…”

Applying DNA barcodes for identification of economically important species in Brassicaceae

“…However, most of the characters considered are subject to convergent evolution, at least on the tribal and subtribal level (Hedge, 1976;Al-Shehbaz, 1984). Within the past two decades, several molecular phylogenetic studies on Brassicaceae (Bailey et al, 2006;Koch et al, 2007;Beilstein et al, 2008;German et al, 2009;Khosravi et al, 2009;Warwick and Hall, 2009;Couvreur et al, 2010;Warwick et al, 2010;German et al, 2011;Goodson et al, 2011) have refined the tribal classification, resurrected several tribes previously misrecognized, added the newly established ones, and adjusted limits of many genera. Despite the substantial progress achieved during the past 20 years along the phylogenetic and systematic fronts of the family, many unresolved problems, especially the limits of tribes and the discrimination of species, remain unaddressed.…”