Yu, Jianing , Raubeson, Linda A. .
RNA Editing in the Chloroplast Genomes of Gymnosperms.
We are investigating RNA editing in gymnosperm chloroplast genomes. RNA editing is relatively abundant in chloroplast genomes of most non-seed land plants, e.g. the hornwort Anthoceros and the fern Adiantum. In these plastomes both C-to-U and U-to-C edits are found. However in the five seed plants that have been fully investigated, no plastid U-to-C sites occur and the overall number of edit sites is greatly reduced. These findings indicate that RNA editing has been reduced over evolutionary time and that the process is not as important in seed plant plastomes. However, the only gymnosperm examined to date is the conifer Pinus thunbergii. We have examined nine genes from the chloroplast genome of the conifer Araucaria heterophylla, selecting genes that commonly contain edited sites. Three genes, psbE, psbF, and psbL, did not exhibit RNA editing. The other genes, atpF, petB, petD, ndhB, ndhD, and ndhH, had one, one, two, five, three or two edited sites, respectively. Eleven of the fourteen edits result in an amino acid change, two are silent, and one results in a stop codon. Most (64.3%) edits occur at the second codon position. Thirteen of the fourteen sites are C-to-U edits. However one site is a rare, but not unknown, edit of G-to-A. Eight reports of G-to-A edits appear in the online RNA edit database, dbRES, none from plastids. When we compare the edited Araucaria amino acid sequences to other edited sequences, we see that the different original cDNAs of all nine genes become very similar in seed plants upon RNA editing. Now we are investigating RNA editing in the Ginkgo biloba plastome.
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1 - Shaanxi Normal University, College of Life Science, 199 Chang'an South Road, Xi'an, Shaanxi, 710062, P.R China
2 - Central Washington University, Biological Sciences, Ellensburg, WA, 98926, U.S.A
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM