A phylogenetic study of subtribe Otachyriinae (Poaceae, Panicoideae, Paspaleae).

ACOSTA, JUAN; REINHEIMER, R.; F.O. ZULOAGA

PLANT SYSTEMATICS AND EVOLUTION

SPRINGER WIEN

Lugar: Viena; Año: 2013

0378-2697

The subtribe Otachyriinae was established, within tribe Paniceae, by Butzin in 1970,originally including 18 genera. Recent phylogenetic studies, based on molecular data,indicated that Otachyriinae belongs to tribe Paspaleae and is represented by thegenera Anthaenantia, Hymenachne, Dallwatsonia, Otachyrium, species of Panicumsect. Laxa, Plagiantha, and Steinchisma. These taxa show a peculiar diversity inphotosynthetic types, including C4 species, C3-C4 intermediates and C3 species. Theinternal evolutionary relationships among members of Otachyriinae have not beenexplored in detailed yet. With the aim of providing new evidence to understandphylogenetic relationships of taxa included in Otachyriinae, 21 new sequences of thendhF gene from 34 species (sobre un total de xx especies consideradas dentro deOtachyriinae) were generated and analyzed using Bayesian Inference and MaximumParsimony. The evolution of the photosynthetic pathway were studied employingmaximum parsimony (MP), Markov chain Monte Carlo (MCMC), and Maximumlikelihood (ML) methods. Our results confirm that subtribe Otachyriinae ismonophyletic. Within the subtribe, Anthaenanthia is a C4 monophyletic genus and thesister group of the remaining species included in this treatment. Hymenachne andPanicum sect. Laxa, in its traditional concept, are polyphyletic genera; Dallwatsonia, P.auritum, and P. hemitomon are treated within Hymenachne while three species ofPanicum sect. Laxa considered as a new genus in the subtribe. The genus Otachyriumrecover as paraphyletic, while all species of Steinchisma are recovered as amonophyletic group with high support. Finally, our data suggest that C4 and C3-C4photosynthesis evolved just once each during the speciation of the subtribe from a C3ancestor.