Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages

Abstract

BackgroundTribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences.ResultsPhylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23–16 million years ago (Ma)) and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba) and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris) is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles.ConclusionsFabeae evolved in the Eastern Mediterranean in the middle Miocene and spread from there across Eurasia, into Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years). Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.

Legume Crops Phylogeny and Genetic Diversity for Science and Breeding

“…(lentil; 4 species); Pisum L. (pea; 2-3 species); Vicia L. (vetch; about 160-200 species) and the monotypic genus Vavilovia Fed. Schaefer et al, 2012). The tribe Fabeae is sister to the Trifolieae tribe (Steele and Wojciechowski, 2003;Schaefer et al, 2012).…”

“…Schaefer et al, 2012). The tribe Fabeae is sister to the Trifolieae tribe (Steele and Wojciechowski, 2003;Schaefer et al, 2012). The tribe is morphologically characterized by mostly paripinnate, often tendrillous leaves and a pubescent style or a pollen brush (Lavin and Delgado, 1990).…”

“…The tribe is morphologically characterized by mostly paripinnate, often tendrillous leaves and a pubescent style or a pollen brush (Lavin and Delgado, 1990). Stylar shapes and hair patterns are one of the principal diagnostic characteristics within the genera of Fabeae (Gunn and Kluve, 1976;Kupicha, 1981;Schaefer et al, 2012). The clade is considered one of the youngest tribes among legumes (Kupicha, 1981;Steele and Wojciechowski, 2003;Wojciechowski et al, 2004;Lock and Maxted, 2005), and estimates based on rates of evolution in the maturase K chloroplast gene place the age of the crown node at 17.5 Mya, in the mid-Miocene (Lavin et al, 2005).…”

Notulae to the Italian alien vascular flora: 3

“…According to the molecular phylogenetic research published by Schaefer et al (2012), the genus Lens Mill. is nested within Vicia L. For the type species of Lens (Lens culinaris Medik.…”

The single evolutionary origin of chlorinated auxin provides a phylogenetically informative trait in the Fabaceae

“…Parochetus) tribes, we also sourced 4 species of Ononis, a genus that may be either basal to the genera Medicago, Melilotus and Trigonella 8,9 or basal to the entire Fabeae and Trifolieae (ex. Parochetus) clades, 10 and which, as a genus, has not yet been tested for auxins in seeds (Fig. 1).…”