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

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

PLANT SYSTEMATICS AND EVOLUTION

SPRINGER WIEN

Lugar: Viena; Año: 2014 vol. 300 p. 2155 - 2166

0378-2697

Abstract The subtribe Otachyriinae was established,within tribe Paniceae, by Butzin in 1970, originallyincluding 18 genera. Recent phylogenetic studies, based onmolecular data, indicated that Otachyriinae belongs to tribePaspaleae and is represented by the genera Anthaenantia,Hymenachne, Dallwatsonia, Otachyrium, species of Panicumsect. Laxa, Plagiantha, and Steinchisma. These taxashow a peculiar diversity in photosynthetic types, includingC4 species, C3?C4 intermediates and C3 species. Theinternal evolutionary relationships among members of Otachyriinaehave not yet been explored in detail. With theaim of providing new evidence to understand phylogeneticrelationships of taxa included in Otachyriinae, 21 newsequences of the ndhF gene from 34 species were generatedand analyzed using Bayesian inference and maximumparsimony (MP). The evolution of photosynthetic pathwaywas studied employing MP, Markov chain Monte Carlo,and maximum likelihood methods. Our results confirm thatsubtribe Otachyriinae is monophyletic. Within the subtribe,Anthaenanthia is a monophyletic C4 genus and is sister tothe remaining species included in this treatment. Hymenachneand Panicum sect. Laxa, in its traditional concept,are polyphyletic; Dallwatsonia, P. auritum, and P. hemitomonare treated within Hymenachne, while three speciesof Panicum sect. Laxa are considered a new genus in thesubtribe. The genus Otachyrium is paraphyletic, while allspecies of Steinchisma are recovered as a monophyleticgroup with high support. Finally, our data suggest that C4and C3?C4 photosynthesis evolved just once each duringthe speciation of the subtribe from a C3 ancestor