title: Acclimation of the crucifer Eutrema salsugineum to phosphate limitation is associated with constitutively high expression of phosphate-starvation genes.
abstract: Eutrema salsugineum, a halophytic relative of Arabidopsis thaliana, was subjected to varying phosphate (Pi) treatments. Arabidopsis seedlings grown on 0.05 mm Pi displayed shortened primary roots, higher lateral root density and reduced shoot biomass allocation relative to those on 0.5 mm Pi, whereas Eutrema seedlings showed no difference in lateral root density and shoot biomass allocation. While a low Fe concentration mitigated the Pi deficiency response for Arabidopsis, Eutrema root architecture was unaltered, but adding NaCl increased Eutrema lateral root density almost 2-fold. Eutrema and Arabidopsis plants grown on soil without added Pi for 4 weeks had low shoot and root Pi content. Pi-deprived, soil-grown Arabidopsis plants were stunted with senescing older leaves, whereas Eutrema plants were visually indistinguishable from 2.5 mm Pi-supplemented plants. Genes associated with Pi starvation were analysed by RT-qPCR. EsIPS2, EsPHT1;4 and EsPAP17 showed up-regulated expression in Pi-deprived Eutrema plants, while EsPHR1, EsWRKY75 and EsRNS1 showed no induction. Absolute quantification of transcripts indicated that PHR1, WRKY75 and RNS1 were expressed at higher levels in Eutrema plants relative to those in Arabidopsis regardless of external Pi. The low phenotypic plasticity Eutrema displays to Pi supply is consistent with adaptation to chronic Pi deprivation in its extreme natural habitat.
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: Vera Marjorie Elauria
authors.initials: VM
authors.lastname: Velasco
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Mansbridge
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: Samantha
authors.initials: S
authors.lastname: Bremner
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Carruthers
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Summers
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.|The Center for Applied Genomics, The Hospital for Sick Children, Peter Giligan Centre for Research and Learning, Toronto, ON, M5G 0A4, Canada.
authors.forename: Wilson W L
authors.initials: WW
authors.lastname: Sung
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.|Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M1C 1A4, Canada.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Champigny
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Weretilnyk
mesh_terms: D000064:Acclimatization; D019607:Brassicaceae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000071825:Extremophiles / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007501:Iron / Q000378:metabolism; D010641:Phenotype; D010710:Phosphates / Q000172:deficiency*; D054712:Salinity; D036226:Seedlings / Q000254:growth & development
chemical_list: D010710:Phosphates; D007501:Iron
keywords: Arabidopsis thaliana; Thellungiella salsuginea; absolute RT-qPCR; extremophile; halophyte; phosphate transporter; phosphorus; stress tolerance