Abstract Detail

Systematics Section / ASPT

Amico, Guillermo C. [1], Vidal-Russell, Romina [2], Nickrent, Daniel [2].

Molecular Phylogeny of Tristerix (Loranthaceae).

The South American endemic mistletoe genus Tristerix (Loranthaceae) consists of eleven species with an andean distributed from Colombia to Chile. Tristerix has been divided into two subgenera, Tristerix (two species) and Metastachys (nine species). This classification was based mainly on the number of petals and the presence of bracteoles. The objective of this work was to reconstruct the phylogeny of the genus using molecular markers. Genomic DNA was extracted for all species except T. peruvianus and T. secundus. More than one individual was included for T. aphyllus, T. corymbosus and T. verticillatus. Three partitions were used for the molecular analysis: the internal transcriber spacer (ITS) of nuclear ribosomal DNA and two noncoding chloroplast spacers (atpB - rbcL and trnL - trnF). Three genera of South American Loranthaceae were used as outgroups. Separate maximum parsimony analyses of the three partitions resulted in congruent tree topologies, thus we conducted a combined analysis. Five subgenus Metastachys species formed a strongly supported clade. Two species (T. verticillatus and T. penduliflorus), previously considered part of Metastachys, were placed on a strongly supported clade with subgenus Tristerix species. Different Tristerix verticillatus accessions are paraphyletic using both chloroplast partitions but this relationship is not obtained with ITS. If a true conflict exists, hybridization with T. aphyllus or/and T. corymbosus is suggested. These three species share the same geographic range and a hummingbird pollen vector (Sephanoides sephaniodes).

1 - Universidad Nacional del Comahue, CRUB, Laboratorio de Ecotono, Quintral 1250, Bariloche, RN, 8400, Argentina
2 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA

Keywords:
trnT-L spacer
interspecific hybridization
ITS
mistletoe
atpB-rbcL spacer.

Presentation Type: Poster
Session: 33-87
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM
Abstract ID:118