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Abstract Detail



Genomics / Proteomics

Naumann , Julia  [1], Der, Joshua [2], Honaas, Loren [2], Wafula, Eric [2], Wagner, Sarah [4], Ralph, Paula [5], Bolin, Jay [6], Maass, Erika [7], Neinhuis, Christoph [1], WANKE, STEFAN [8], dePamphilis, Claude [9].

The smallest plastid genome in flowering plants found in the holoparasitic Hydnora visseri (Hydnoraceae).

Photosynthetic ability has been lost in multiple independent flowering plant lineages. Unlike the highly conserved chloroplast genome of photosynthetic plants, the plastid genome of parasitic plants can be highly reduced in both size and gene content due to the release from selective constraint. Plastomes of holoparasitic plants are greatly reduced in size after full commitment to the parasitic lifestyle. Here we show the most minimal of all plastomes sequenced to date, the plastome of Hydnora visseri (Hydnoraceae, Piperales). Organellar scaffolds were identified in assemblies of Illumina genomic sequence using a BLAST approach. Compared to the close relative Piper (Piperaceae), the gene content of Hydnora is reduced from 113 to 10 genes or pseudogenes and from the total size from 160 kb to 24 kb. In contrast, the mitochondrial genome of Hydnora occupied 50 scaffolds with a total length of over 1.5 Mb. In addition to the sequences on the plastid scaffold, 20 more plastid-derived sequences have been identified on mitochondrial scaffolds. The stoichiometry of the plastid scaffold is over two orders of magnitude greater than the mitochondrial scaffolds, indicating the independent occurrence of these sequences in the cell. While few full length genes are found on the plastid scaffold, only non-functional fragments of plastid genes can be found scattered across the mitochondrial scaffolds. This suggests a previous integration of plastid DNA into the mitochondrial genome followed by disorganization. Currently it remains unclear why a tiny plastome has persisted in an ancient parasitic lineage that shifted from autotrophy to holoparasitism between 90 to 50 MY ago.


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1 - TU Dresden, Institut fuer Botanik, 01062, Germany
2 - Penn State University, Department Of Biology, 201 Life Sciences Building, University Park, PA, 16802, USA
3 - Penn State University, Department Of Biology, 201 Life Sciences Building, University Park, PA, 16802, USA
4 - Institute For Botany, Zellescher Weg 20b, Dresden, N/A, 01062, Germany
5 - Penn State University, Department Of Biology, 201 Life Sciences Building, University Park, PA, 16802, USA
6 - Catawba College, 2300 W Innes, St. Salisbury, NC, 28144, USA
7 - University of Namibia, Department of Biological Sciences, Windhoek, Namibia
8 - TU Dresden, Dept. Of Biology, Institut Of Botany, Zellescher Weg 20b, Dresden, N/A, 01062, Germany
9 - Pennsylvania State University, Department Of Biology, 101 LIFE SCIENCES BUILDING, UNIVERSITY PARK, PA, 16802, USA

Keywords:
plastid genome
mitochondrial genome
parasitic plants
Piperales.

Presentation Type: Oral Paper:Papers for Topics
Session: 35
Location: Pines South/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 10:15 AM
Number: 35009
Abstract ID:545
Candidate for Awards:Margaret Menzel Award


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