Submitted to: Journal American Society Hortscience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2004
Publication Date: 6/6/2005
Citation: Griesbach, R.J., Beck, R.M. 2005. Sequence analysis of the chalcone synthase gene in four Petunia taxa. J. Amer. Soc. Hort. Sci. 130:360-365. Interpretive Summary: Near the town of Torres in Brazil, a unusual petunia was found with round succulent and glabrous leaves. The morphology of this petunia did not match any known species; therefore, it was not possible to assign this plant a name. Molecular markers were used to compare this plant with known species in order to determine if it was a new species. One of the genes in the flower color pathway was used to characterize those petunia species with morphology similar to the unusual plant from Torres. The DNA sequence of the gene was determined and compared. The comparison suggested that the Torres plant was an unusual form of Petunia integrifolia subsp. integrifolia var. depauperata.
Technical Abstract: In order to study the phylogenetic relationships of closely related species, non-coding sequences that have accumulated a wide array of mutations should be analyzed. The intron in the chalcone synthase gene intron is a highly variable sequence that can be easily amplified with PCR and sequenced. The sequence of this intron was used to characterize P. integrifolia subsp. integrifolia var. depauperata, P. altiplana, P. littoralis and an unknown taxon from the town of Torres in Brazil. Based upon the intron, the Torres taxon most closely resembled P. integrifolia. The unrooted phylogenetic tree suggested that P. integrifolia was more closely related to P. littoralis than P. altiplana.