YANG, L.1*, K. STEELE1, and M. LAVIN2. 1California State University, Hayward; 2Montana State University, Bozeman. - Phylogenetic analyses of selected genera of subfamily Papilionoideae, using nucleotide sequence data of the nuclear-encoded gibberellic acid 20-oxidase genesof.
The gibberellic 20-oxidases are important enzymes that catalyze some
of the later steps in the gibberellic acid biosynthetic pathway. The
GA 20-oxidases are encoded by three nuclear of a gene family that
encodes other enzymes active in the gibberellic acid biosynthetic
pathway, such as 3b-hydroxyase encoded by Mendel’s stem length gene
Le. The GA 20-oxidases are members of the 2-oxoglutarate dependent
dioxygenase group of enzymes. The genes encoding the three GA
20-oxidases have diverged sufficiently so as to make it possible to
design ortholog specific primers for each paralog using published
sequence data from Pisum, Phaseolus, and Glycine. We are using these
sequence data to test or provide additional support for selected
phylogenetic relationships among genera in subfamily Papilionoideae
that have been hypothesized on the basis of morphological data and/or
phylogenetic analyses of the family based on chloroplast gene
sequences. Two examples are as follows. Phylogenetic analyses of matK
data indicate that Trifolium is basal to a clade composed of genera in
the Vicieae, Vicia, Lens, Pisum, and Lathyrus rather than being in a
clade with other genera in the Trifolieae, the tribe in which
Trifolium is placed. The relationship suggested by matK data is
supported by phylogenetic analyses of genes encoding GA 20-oxidases.
Within the Millettieae/Phaseoleae clade analyses of matK data indicate
that Dalbergiella is sister to a clade consisting of core Millettieae,
Phaseoleae and related genera, but this relationship is weakly
supported; however analyses of genes encoding GA 20-oxidases provide
strong support for this relationship. Genes encoding GA 20-oxidases
provide phylogenetically informative characters that support a number
of hypothesized relationships within subfamily Papilionoideae.
Key words: Fabaceae, nuclear-encoded genes, phylogenetic analyses