Mitochondrial DNA suggests at least 11 origins of parasitism in angiosperms and reveals genomic chimerism in parasitic plants

Some of the most difficult phylogenetic questions in evolutionary biology involve identification of the free-living relatives of parasitic organisms, particularly those of parasitic flowering plants. Consequently, the number of origins of parasitism and the phylogenetic distribution of the heterotro...

Full description

Saved in:

Bibliographic Details
Published in:	BMC evolutionary biology Vol. 7; no. 1; p. 248
Main Authors:	Barkman, Todd J, McNeal, Joel R, Lim, Seok-Hong, Coat, Gwen, Croom, Henrietta B, Young, Nelson D, Depamphilis, Claude W
Format:	Journal Article
Language:	English
Published:	England BioMed Central Ltd 21-12-2007 BioMed Central BMC
Subjects:	Angiosperms Chimera - genetics DNA, Mitochondrial - genetics DNA, Plant - genetics Evolution, Molecular Gene Transfer, Horizontal Genetic aspects Genome, Plant Magnoliopsida - genetics Mitochondrial DNA Parasitic plants Phylogeny Symbiosis United States
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Some of the most difficult phylogenetic questions in evolutionary biology involve identification of the free-living relatives of parasitic organisms, particularly those of parasitic flowering plants. Consequently, the number of origins of parasitism and the phylogenetic distribution of the heterotrophic lifestyle among angiosperm lineages is unclear. Here we report the results of a phylogenetic analysis of 102 species of seed plants designed to infer the position of all haustorial parasitic angiosperm lineages using three mitochondrial genes: atp1, coxI, and matR. Overall, the mtDNA phylogeny agrees with independent studies in terms of non-parasitic plant relationships and reveals at least 11 independent origins of parasitism in angiosperms, eight of which consist entirely of holoparasitic species that lack photosynthetic ability. From these results, it can be inferred that modern-day parasites have disproportionately evolved in certain lineages and that the endoparasitic habit has arisen by convergence in four clades. In addition, reduced taxon, single gene analyses revealed multiple horizontal transfers of atp1 from host to parasite lineage, suggesting that parasites may be important vectors of horizontal gene transfer in angiosperms. Furthermore, in Pilostyles we show evidence for a recent host-to-parasite atp1 transfer based on a chimeric gene sequence that indicates multiple historical xenologous gene acquisitions have occurred in this endoparasite. Finally, the phylogenetic relationships inferred for parasites indicate that the origins of parasitism in angiosperms are strongly correlated with horizontal acquisitions of the invasive coxI group I intron. Collectively, these results indicate that the parasitic lifestyle has arisen repeatedly in angiosperm evolutionary history and results in increasing parasite genomic chimerism over time.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1471-2148 1471-2148
DOI:	10.1186/1471-2148-7-248