Systematics Section / ASPT
Robadey, Talline M. , Barkman, Todd J. .
Reconstruction of Solanaceae Phylogeny Using the Nuclear Gene SAMT.
The Solanaceae is a widely known plant family of great economic importance that includes agriculturally significant plants such as tomato, potato, and pepper. Consequently, this family has received much phylogenetic attention. At the family-level, phylogenetic studies based on chloroplast DNA have resulted in an overall well-supported set of intergeneric relationships. However, corroboration of Solanaceae evolutionary history from an independent genome is still lacking. Furthermore, an independent data set could provide additional support for weakly supported nodes and resolution of the currently ambiguous placement of some taxa. In this study, we used a nuclear gene to reconstruct Solanaceae phylogeny at the intrafamilial level. The chosen gene, Salicylic Acid Methyl Transferase (SAMT), is responsible for the biosynthesis of methyl salicylate, a compound commonly found in floral scent. Reverse Transcriptase PCR was used to isolate SAMT from 23 species representing 14 of 16 tribes and 6 of 7 subfamilies in the Solanaceae. The amplified cDNAs were sequenced and subsequently aligned using ClustalX. All phylogenetic analyses were performed using PAUP*4.0. Overall, our results supported the previous phylogenetic hypotheses obtained using cp data, but some differences were found and are worth noting, including the position of Nicandra. Nicandra was not found to be sister to Exodeconus as previously shown; instead, it appears to belong to a lineage including Solanum, Physalis, and Capsicum. The placement of Exodeconus remained ambiguous at the base of the subfamily Solanoideae. Analyses using combined nuclear and cp DNA data resulted in a better-resolved and supported tree in comparison to the topologies obtained with either dataset independently. These results indicate that expanded sampling of taxa for SAMT and the study of additional nuclear gene sequences will be valuable towards improving our understanding of Solanaceae phylogeny.
1 - Western Michigan University, Department of Biological Sciences, 1903 West Michigan Ave, Kalamazoo, Michigan, 49008, USA
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 4:15 PM