title: Root spatial metabolite profiling of two genotypes of barley (Hordeum vulgare L.) reveals differences in response to short-term salt stress.
abstract: Barley (Hordeum vulgare L.) is the most salt-tolerant cereal crop and has excellent genetic and genomic resources. It is therefore a good model to study salt-tolerance mechanisms in cereals. We aimed to determine metabolic differences between a cultivated barley, Clipper (tolerant), and a North African landrace, Sahara (susceptible), previously shown to have contrasting root growth phenotypes in response to the early phase of salinity stress. GC-MS was used to determine spatial changes in primary metabolites in barley roots in response to salt stress, by profiling three different regions of the root: root cap/cell division zone (R1), elongation zone (R2), and maturation zone (R3). We identified 76 known metabolites, including 29 amino acids and amines, 20 organic acids and fatty acids, and 19 sugars and sugar phosphates. The maintenance of cell division and root elongation in Clipper in response to short-term salt stress was associated with the synthesis and accumulation of amino acids (i.e. proline), sugars (maltose, sucrose, xylose), and organic acids (gluconate, shikimate), indicating a potential role for these metabolic pathways in salt tolerance and the maintenance of root elongation. The processes involved in root growth adaptation and the underlying coordination of metabolic pathways appear to be controlled in a region-specific manner. This study highlights the importance of utilizing spatial profiling and will provide us with a better understanding of abiotic stress response(s) in plants at the tissue and cellular level.
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond SA 5064, Australia megan.shelden@adelaide.edu.au.
authors.forename: Megan C
authors.initials: MC
authors.lastname: Shelden
authors.affiliation: Metabolomics Australia, The University of Melbourne, Parkville VIC 3010, Australia.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Dias
authors.affiliation: Metabolomics Australia, The University of Melbourne, Parkville VIC 3010, Australia.
authors.forename: Nirupama S
authors.initials: NS
authors.lastname: Jayasinghe
authors.affiliation: Metabolomics Australia, The University of Melbourne, Parkville VIC 3010, Australia ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville VIC 3010, Australia.
authors.forename: Antony
authors.initials: A
authors.lastname: Bacic
authors.affiliation: Metabolomics Australia, The University of Melbourne, Parkville VIC 3010, Australia School of BioSciences, The University of Melbourne, Parkville VIC 3010, Australia.
authors.forename: Ute
authors.initials: U
authors.lastname: Roessner
mesh_terms: D002122:Calcium Chloride / Q000494:pharmacology; D005838:Genotype; D001467:Hordeum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological
chemical_list: D012965:Sodium Chloride; D002122:Calcium Chloride
keywords: Cell division; cereal; gas chromatography–mass spectrophotometry; metabolomics; osmotic stress; root elongation; root growth; salinity.