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Abstract Detail

Genomics / Proteomics

Guo, Wenhu [1], Mower, Jeff [1].

Complete mitochondrial genomes from the ferns Ophioglossum californicum and Psilotum nudum are highly repetitive with the largest organellar introns.

To date, complete mitochondrial genomes (mitogenomes) are available from all major land plant lineages except ferns (Monilophyta), the immediate sister lineage of seed plants (Spermatophyta). Sequencing of fern mitogenomes could shed light on the origin of complex mitogenomic features in vascular plants and the major evolutionary transitions that established mitogenomic diversity among extant lineages. In this study, we generated the first two complete mitogenomes from ferns: the adder’s tongue fern (Ophioglossum californicum) and the whisk fern (Psilotum nudum). The mitogenome from Psilotum is arranged in two chromosomes of 364 kb and 264 kb. It has retained nearly all genes inherited from the vascular plant ancestor and contains a rich complement of introns, most of which are shared with other vascular plants. Comparative analysis demonstrated that the Psilotum mitogenome has the largest organellar genes and introns of any green plant, and the introns may be the largest from any eukaryotic organellar genome. In the 372 kb Ophioglossum mitogenome, gene and intron content is slightly reduced, involving the loss of all 4 ccm genes whose products are involved in cytochrome c maturation and the loss of 5 introns. Both fern mitogenomes are highly repetitive, yet they show extremely low levels of active recombination, even at large repeats. Transcriptomic sequencing uncovered ~1000 sites of C-to-U RNA editing in both species, plus a small number (<60) of U-to-C edit sites. Overall, the first mitochondrial genomes of ferns show a mix of features shared with lycophytes and/or seed plants and several novel genomic features, consistent with their unique evolutionary position among vascular plants.

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1 - University of Nebraska-Lincoln, Center for Plant Science Innovation, Lincoln, NE, 68588, USA

mitochondrial genome
repetitive DNA
RNA editing

Presentation Type: Oral Paper
Session: 19, Genomics & Proteomics I
Location: 105/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 11:30 AM
Number: 19014
Abstract ID:806
Candidate for Awards:None

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