title: ESKIMO1 disruption in Arabidopsis alters vascular tissue and impairs water transport.
abstract: Water economy in agricultural practices is an issue that is being addressed through studies aimed at understanding both plant water-use efficiency (WUE), i.e. biomass produced per water consumed, and responses to water shortage. In the model species Arabidopsis thaliana, the ESKIMO1 (ESK1) gene has been described as involved in freezing, cold and salt tolerance as well as in water economy: esk1 mutants have very low evapo-transpiration rates and high water-use efficiency. In order to establish ESK1 function, detailed characterization of esk1 mutants has been carried out. The stress hormone ABA (abscisic acid) was present at high levels in esk1 compared to wild type, nevertheless, the weak water loss of esk1 was independent of stomata closure through ABA biosynthesis, as combining mutant in this pathway with esk1 led to additive phenotypes. Measurement of root hydraulic conductivity suggests that the esk1 vegetative apparatus suffers water deficit due to a defect in water transport. ESK1 promoter-driven reporter gene expression was observed in xylem and fibers, the vascular tissue responsible for the transport of water and mineral nutrients from the soil to the shoots, via the roots. Moreover, in cross sections of hypocotyls, roots and stems, esk1 xylem vessels were collapsed. Finally, using Fourier-Transform Infrared (FTIR) spectroscopy, severe chemical modifications of xylem cell wall composition were highlighted in the esk1 mutants. Taken together our findings show that ESK1 is necessary for the production of functional xylem vessels, through its implication in the laying down of secondary cell wall components.
authors.affiliation: Institut Jean-Pierre Bourgin UMR1318 INRA-AgroParisTech, INRA Centre de Versailles-Grignon, Versailles, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Lefebvre
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Fortabat
authors.forename: Aloïse
authors.initials: A
authors.lastname: Ducamp
authors.forename: Helen M
authors.initials: HM
authors.lastname: North
authors.forename: Alessandra
authors.initials: A
authors.lastname: Maia-Grondard
authors.forename: Jacques
authors.initials: J
authors.lastname: Trouverie
authors.forename: Yann
authors.initials: Y
authors.lastname: Boursiac
authors.forename: Gregory
authors.initials: G
authors.lastname: Mouille
authors.forename: Mylène
authors.initials: M
authors.lastname: Durand-Tardif
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D000123:Acetyltransferases; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002473:Cell Wall / Q000378:metabolism; D002482:Cellulose / Q000096:biosynthesis; D008565:Membrane Proteins; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D014867:Water; D000040:Abscisic Acid; D002482:Cellulose; D000123:Acetyltransferases; C523203:At3g55990 protein, Arabidopsis; D011494:Protein Kinases; C472139:OST1 protein, Arabidopsis