INVESTIGADORES
DENHAM silvia Suyai
artículos
Título:
Origin and evolution of Atriplex (Amaranthaceae s.l.) in the Americas: Unexpected insights from South American species
Autor/es:
BRIGNONE, NICOLÁS F.; POZNER, RAÚL E.; DENHAM, SILVIA S.
Revista:
TAXON
Editorial:
INT ASSOC PLANT TAXONOMY
Referencias:
Año: 2019 vol. 68 p. 1021 - 1036
ISSN:
0040-0262
Resumen:
With ca. 300 species of herbs, shrubs and subshrubs adapted to saline or alkaline soils, the evolution of the genus Atriplex iskey to understand the development of semi-arid environments worldwide. Previous phylogenetic analyses of Atriplex, including only afew species from South America, especially in comparisonwith North American species represented, proposed a North American originfor the South American Atriplex, through more than one dispersal event. Since South America is one of the four centres of Atriplex diversity,with a high number of endemic species, awider and more representative sampling of this region is essential to understand the originand evolution of the genus Atriplex in the Americas. We performed a phylogenetic analysis with estimated clade ages and an ancestralrange estimation focused on theAmerican species of Atriplex, to identify SouthAmerican lineages, their relationshipswith other lineagesof the genus (and particularly with North American ones), and to unravel their biogeographical history in the Americas. Phylogeneticanalyses were conducted with sequence data from ITS, ETS and atpB-rbcL spacer markers, using maximum parsimony, Bayesian inferenceand maximum likelihood approaches. The DEC+J model implemented in BioGeoBEARS was applied in order to infer ancestralranges. The Americas were colonized by Atriplex in two independent dispersal events: (1) the C4 Atriplex from Eurasia or Australia,and (2) the C3 Atriplex (represented only by the extant A. chilensis) fromEurasia. The C4American lineage of Atriplex originated roughly10.4 Ma (95% HPD = 13.31?7.62 Myr) in South America, where two lineages underwent in situ diversification and evolved sympatrically.North America was colonized by Atriplex from South America; later, one lineage moved from North America to South America.Most of the extant species have arisen in the last 3?4 Myr, inPliocene?Pleistocene. We detected some South American taxa differing inposition between both nuclear and atpB-rbcL spacer partitions, which could be explained by chloroplast capture.