title: Investigating the drought-stress response of hybrid poplar genotypes by metabolite profiling.
abstract: Drought stress is perhaps the most commonly encountered abiotic stress plants experience in the natural environment, and it is one of the most important factors limiting plant productivity. Here, we employed untargeted metabolite profiling to examine four drought-stressed hybrid poplar (Populus spp.) genotypes for their metabolite content, using gas chromatography coupled to mass spectrometry. The primary objective of these analyses was to characterize the metabolite profile of poplar trees to assess relative drought resistance and to investigate the underlying biochemical mechanisms employed by the genotypes to combat drought. Metabolite profiling identified key metabolites that increased or decreased in relative abundance upon exposure to drought stress. Overall, amino acids, the antioxidant phenolic compounds catechin and kaempferol, as well as the osmolytes raffinose and galactinol exhibited increased abundance under drought stress, whereas metabolites involved in photorespiration, redox regulation and carbon fixation showed decreased abundance under drought stress. One clone in particular, Okanese, displayed unique responses to the imposed drought conditions. This clone was found to have higher leaf water potential, but lower growth rate relative to the other clones tested. Okanese also had lower accumulation of osmolytes such as raffinose, galactinol and proline, but higher overall levels of antioxidants such as catechin and dehydroascorbic acid. As such, it was proposed that osmotic adjustment as a mechanism for drought avoidance in this clone is not as well developed in comparison with the other clones investigated in this study, and that a possible alternative mechanism for the enhanced drought avoidance displayed by Okanese may be due to differential allocation of resources or better retention of water.
authors.affiliation: Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4.
authors.forename: Genoa L H
authors.initials: GL
authors.lastname: Barchet
authors.affiliation: Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 Present address: Faculty of Sciences, Plant Biology & Innovation Research Unit EA3900-UPJV, Université of Picardie Jules Verne, PRES UFECAP, Ilot des poulies, 33 rue Saint Leu, F-80039 Amiens Cedex, France.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Dauwe
authors.affiliation: Department of Forest and Conservation Sciences, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Guy
authors.affiliation: Agroforestry Development Centre, Agriculture and Agri-Food Canada, PO Box 940, No. 2 Government Road, Indian Head, SK, Canada S0G 2K0.
authors.forename: William R
authors.initials: WR
authors.lastname: Schroeder
authors.affiliation: Agroforestry Development Centre, Agriculture and Agri-Food Canada, PO Box 940, No. 2 Government Road, Indian Head, SK, Canada S0G 2K0.
authors.forename: Raju Y
authors.initials: RY
authors.lastname: Soolanayakanahally
authors.affiliation: Centre for the Analysis of Genome Evolution & Function, Department of Cell & Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S 3B2 Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada M1C 1A4.
authors.forename: Malcolm M
authors.initials: MM
authors.lastname: Campbell
authors.affiliation: Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 shawn.mansfield@ubc.ca.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Mansfield
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002678:Chimera; D004187:Disaccharides / Q000378:metabolism; D055864:Droughts; D014644:Genetic Variation; D005838:Genotype; D008293:Malates / Q000378:metabolism; D055432:Metabolomics; D009995:Osmosis; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D032107:Populus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D011887:Raffinose / Q000378:metabolism; D014197:Trees; D014867:Water / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D004187:Disaccharides; D008293:Malates; D014867:Water; C013536:6 beta-galactinol; C030298:malic acid; D011887:Raffinose
keywords: genotypic variation; metabolite profiling; osmotic adjustment; poplar