OH, SANG-HUN* and DANIEL POTTER. Department of Pomology, University of California, Davis, CA 95616. - Phylogenetic relationships in tribe Neillieae (Rosaceae) inferred from DNA sequences.
Tribe Neillieae, characterized within Rosaceae by stipulated simple
leaves, ovoid seeds, and copious endosperm, comprises three
taxonomically difficult genera, Neillia, Stephanandra,
and Physocarpus. As part of a comprehensive systematic study of
the tribe, nucleotide sequences of the ITS and 3’ partial ETS regions
of nrDNA, trnL-trnF and trnD-trnT regions
of cpDNA, and the second intron of a floral homeotic gene,
LEAFY, were determined to elucidate phylogenetic relationships
in the tribe Neillieae. The maximum parsimony analyses of nrDNA and
cpDNA data set indicate that two major clades (Physocarpus and
Neillia/Stephanandra) are strongly supported in tribe
Neillieae, but the relationship between Neillia and
Stephanandra is inconsistent. The level of sequence divergence
of the second intron of LEAFY is about 5-fold higher than that
of nrDNA and the intron sequences are phylogenetically useful.
Separate phylogenetic analyses of three data sets (nrDNA, cpDNA, and
LEAFY) suggest that the P. opulifolius complex may have
been originated by a hybridization between P. monogynus and
P. capitatus. The results also suggest that Stephanandra
may be of hybrid origin.
Key words: cpDNA, LEAFY, Neillieae, nrDNA, Phlogeny, Rosaceae