BORTIRI, ESTEBAN1*, SANG-HUN OH1, FANG-YOU GAO1, JIANGUO JIANG2, SCOTT BAGGETT1,3, ANDREW GRANGER4, CLAY WEEKS5, MEGAN BUCKINGHAM1, DAN POTTER1, and DAN E. PARFITT1. 1Department of Pomology, University of California, One Shields Avenue Davis, California 95616; 2Department of Horticulture, Southwest Agricultural University, China; 3Biology Department, Lehman College, 250 Bedford Park Boulevard West, Bronx, New York, 10468-1589; 4South Australian Research and Development Institute (SARDI), Australia; 5National Clonal Germplasm Repository, University of California, One Shields Avenue, Davis, California 95616. - Phylogenetics of Prunus (Rosaceae) as determined by ITS, the chloroplast trnL-trnF spacer and s6pdh: implications for subgeneric classification, biogeography and evolution of morphology.
Phylogeny of Prunus was reconstructed by maximum parsimony
analysis of three markers, ITS, s6pdh and the chloroplast
spacer trnL-trnF. Over forty species from all subgenera and
most sections of Prunus were included in the analyses of ITS
and trnL-trnF. ITS provided more informative sites but was
highly homoplastic, whereas trnL-trnF was less variable and
showed little homoplasy. Combined analysis of these two markers
separated Prunus into two groups; a well supported
Cerasus /Padus /Laurocerasus clade and a second
group that contained the rest of Prunus. The data suggest a
Eurasian origin for Prunus with multiple radiations into North
America. A subset of the samples were selected for phylogeny
reconstruction using s6pdh, a nuclear gene encoding an enzyme
involved in sorbitol metabolism. Fourteen species of Prunus,
representing all major clades found by the previous study using ITS
and trnL-trnF, were included. Maximum parsimony analysis of
s6pdh sequences agrees with results obtained with ITS and
trnL-trnF. Some changes in the classification of Prunus
are necessary. For example it is evident that section
Microcerasus, previously placed in subgenus Cerasus, is
actually more closely related to subgenus Prunus. Evolution of
morphological traits such as dry fruits, and their ecological
significance are discussed
Key words: ITS, phylogenetics, Prunus, s6pdh, trnL-trnF