Braukmann, Thomas , Stefanovic, Sasa .
Comparative plastid genome evolution in mycoheterotrophic Ericaceae.
Heterotrophic plants exhibit a wide range of evolutionary degradation of photosynthetic ability and rely entirely or partially on their hosts to supply water and nutrients. These plants are divided into two distinct, but evolutionary artificial groups, parasitic and mycoheterotrophic plants. Haustorial parasitism has evolved at least 11 times independently and there are at least 10 independent origins of mycoheterotrophy in angiosperms. Each lineage represents an independent origin of heterotrophy and heterotrophs are not well characterized outside a few well-studied examples. Ericaceae, the heather family, is a large and diverse group of plants with elaborate symbiotic relationships with mycorrhizal fungi, including several mycoheterotrophic lineages. Grounded within a phylogenetic framework and broad taxonomic sampling, a comparative investigation of plastid genomes was conducted in the family usinga slot-blot Southern hybridization approach. This survey contained lineages within Ericaceae with different life histories and trophic levels, including multiple representatives from the hemi-mycoheterotrophic pyroloids and holo-mycoheterotrophic monotropoids. A number of fully photosynthetic (autotrophic) members were included to best represent the other major clades within Ericaceae. This survey used 55 probes derived from all categories of protein-coding genes typically found inthe plastomes of photosynthetic plants. Our results indicate that monotropoids exhibit extensive loss off genes relating to photosynthetic function and retain genes with possible function outside photosynthesis. Furthermore, hemi-mycoheterotrophic plants retain most genes relating to photosynthesis but are polymorphic for the plastid ndh genes. Our survey extends previous inferences that plastid gene losses occur prior to becoming holo-heterotrophic and that mycoheterotrophic Ericaceae exhibit gene losses similar in pattern to parasitic plants.
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1 - University Of Toronto At Mississauga, Department Of Biology, 3359 Mississauga Rd N, Mississauga, ON, L5L 1C6, Canada
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell C/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 11:45 AM