Freudenstein, John , Barrett, Craig F. , Yukawa, Tomohisa .
Corallorhiza (Orchidaceae) has two copies of matK, one of which is a pseudogene.
Corallorhiza Gagnebin (Orchidaceae) comprises eleven species of leafless, rootless, mycotrophic orchids. Closely related genera (Aplectrum, Cremastra, and Oreorchis) all possess leaves and roots. Two copies of matK were amplified among species or Corallorhiza, Oreorchis and Aplectrum. One corresponds to the standard ortholog that is known from angiosperm chloroplast genomes, while the other can be almost 400 bp shorter. The latter, which is a pseudogene, amplifies preferentially with commonly used matK primers and has a very high degree of sequence similarity to the standard ortholog. In addition to a large deletion of up to 380 bp at the 5’ end of the ORF, there are several non-triplet insertions and deletions that would render a highly altered and shortened amino acid sequence. While matK has been reported to be a pseudogene in various orchid groups, there is little conclusive evidence outside of Corallorhiza that this is true. Previous phylogenetic analysis of ITS and matK sequences showed Corallorhiza to be monophyletic, but here we find that with increased sampling from Oreorchis, the plastid DNA pattern in particular casts doubt on the monophyly of Corallorhiza, with some species of Oreorchis grouping with the C. striata group and others with the C. maculata group. This would imply a parallel loss of leaves in these two groups of Corallorhiza.
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1 - Ohio State University Herbarium, Dept of Evolution, Ecology and Organismal Biology, 1315 Kinnear Rd., Columbus, OH, 43212, USA
2 - Ohio State University Herbarium, Dept of Evolution, Ecology and Organismal Biology, 1315 Kinnear Rd., Columbus, Ohio, 43212, USA
3 - National Science Museum, Department of Botany, 4-1-1 Amakubo, Tsukuba, 305-0005, Japan
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 4:30 PM