title: Identification of multiple lipid genes with modifications in expression and sequence associated with the evolution of hydroxy fatty acid accumulation in Physaria fendleri.
abstract: Two Brassicaceae species, Physaria fendleri and Camelina sativa, are genetically very closely related to each other and to Arabidopsis thaliana. Physaria fendleri seeds contain over 50% hydroxy fatty acids (HFAs), while Camelina sativa and Arabidopsis do not accumulate HFAs. To better understand how plants evolved new biochemical pathways with the capacity to accumulate high levels of unusual fatty acids, transcript expression and protein sequences of developing seeds of Physaria fendleri, wild-type Camelina sativa, and Camelina sativa expressing a castor bean (Ricinus communis) hydroxylase were analyzed. A number of potential evolutionary adaptations within lipid metabolism that probably enhance HFA production and accumulation in Physaria fendleri, and, in their absence, limit accumulation in transgenic tissues were revealed. These adaptations occurred in at least 20 genes within several lipid pathways from the onset of fatty acid synthesis and its regulation to the assembly of triacylglycerols. Lipid genes of Physaria fendleri appear to have co-evolved through modulation of transcriptional abundances and alterations within protein sequences. Only a handful of genes showed evidence for sequence adaptation through gene duplication. Collectively, these evolutionary changes probably occurred to minimize deleterious effects of high HFA amounts and/or to enhance accumulation for physiological advantage. These results shed light on the evolution of pathways for novel fatty acid production in seeds, help explain some of the current limitations to accumulation of HFAs in transgenic plants, and may provide improved strategies for future engineering of their production.
authors.affiliation: Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Horn
authors.affiliation: Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.|Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Jinjie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, Ohio, USA.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Cocuron
authors.affiliation: Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: McGlew
authors.affiliation: Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Thrower
authors.affiliation: Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Matt
authors.initials: M
authors.lastname: Larson
authors.affiliation: Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Chaofu
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, Ohio, USA.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Alonso
authors.affiliation: Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.|Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA.
authors.forename: John
authors.initials: J
authors.lastname: Ohlrogge
mesh_terms: D019607:Brassicaceae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005227:Fatty Acids / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D050356:Lipid Metabolism / Q000235:genetics*; D060847:Metabolic Engineering; D030821:Plants, Genetically Modified / Q000378:metabolism
chemical_list: D005227:Fatty Acids
keywords: Camelina sativa; Physaria fendleri; RNA-Seq; evolution; hydroxy fatty acids; metabolic engineering; oilseeds; transcriptomics