Molecular phylogeny of Onobrychis sect. Onobrychis (Fabaceae-Hedysareae) with insights into its taxonomy and character evolution

Abstract

Onobrychis sect. Onobrychis, as the most species-rich section of the genus Onobrychis, ranges from Central Asia to Europe with a south extension into North Africa. In this study, we concentrated on the systematics of previously poorly represented O.sect. Onobrychis using a substantial taxon sampling. To test the monophyly of the section as well as to clarify interspecific relationships, the nuclear ribosomal DNA internal transcribed spacer(nrDNA ITS) and three chloroplast sequences (ndhF-rlp32, rpl32-trnL(UAG), and trnG(UCC)-trnS(GCU)) were employed. Phylogenetic analyses were performed by maximum likelihood and Bayesian inferences. The results showed that O.sect. Onobrychis is monophyletic and composed of two main well-supported clades which are redefined as two subsections (O.subsect. Onobrychis, O. subsect. Macropterae).Ancestral character reconstruction of morphological traits: life form, wing to standard ratio, chromosome number, and ploidy level, indicated that short-winged petal is a synapomorphy for a group of species in the section while other traits have undergone parallel evolution. Possessing the basic chromosome number x= 7 has arisen twice, independently. It seems that perenniality and polyploidy are probably the key innovations in the diversification of O. sect. Onobrychis.

Evolutionary history of an Irano-Turanian cushion-forming legume (Onobrychis cornuta)

“…The utilization of BEAST analysis has provided valuable insights into the origin and subsequent diversification of Onobrychis in the context of the climatic conditions during the Middle Miocene through the Pleistocene, which is consistent with the time estimation of previous studies [ 16 , 49 ] (Fig. 6 ).…”

“…This species, along with other congeneric species, has been studied from various perspectives, including gross morphology [e.g., 9, 6], karyology [ 18 – 21 ], fruit morphology [ 22 ], palynology [ 23 , 24 ], genetic diversity [ 25 ], and molecular phylogeny [ 15 , 16 , 26 ]. Moreover, the species has been solely subject of the other research areas, such as community ecology [ 27 ], ecological niche modeling [ 28 ] and mountainous rangeland management [ 29 , 30 ].…”