|Ballard, Jr, Harvey - OH UNIV PLANT BIOLOGY|
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2003
Publication Date: January 15, 2004
Citation: Stephenson, S.A., Spooner, D.M., Ballard, Jr, H.E. 2004. Nuclear ribosomal internal transcribed spacer region (its) dna sequence phylogeny of wild potatoes (solanum section petota) [abstract]. Plant and Animal Genome Conference. p.80. Technical Abstract: There remain many unresolved questions of interspecific relationships in potato (Solanum sect. Potota). A recent taxonomic classification by Hawkes recognized 21 taxonomic series, yet chloroplast DNA (cpDNA) restriction site data supported only four main clades (American Journal of Botany, 84: 671-685). This study used DNA sequence data from the internal transcribed spacer region of nuclear ribosomal DNA (ITS) to explore relationships of 92 accessions of section Petota representing 18 of the 21 series, and five additional outgroups in Capsicum, Datura, and other Solanum outside of section Petota. The outgroup results are concordant with the chloroplast DNA data in supporting members of Hawkes's two non-tuber-bearing sections as outgroups to sect. Petota (that we recognize as sect. Etuberosum and sect. Lycopersicon) but bootstrap support for this result is low. Ingroup results in section Petota support two main clades: 1) combining species from cpDNA clades 1 + 2 + 3, and 2) members of cpDNA clade 4. However, bootstrap support for these clades also is low. A few well-defined (high bootstrap support) internal branches provide strong support for relationships inferred from other data (e.g., the sister-taxon relationships of S. demissum and species in ser. Acaulia, or of S. clarum and S. morelliforme). Conversely, strong discordance with the cpDNA results suggest a history of 'chloroplast capture;' e.g., ITS-supported relationships for S. bulbocastanum, S. cardiophyllum and S. ehrenbergii, where S. ehrenbergii is well separated with cpDNA results.