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On plant responses to D-amino acids

features of growth, root behaviour and selection for plant transformation

Forsum, Oskar (2016). On plant responses to D-amino acids. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2016:19
ISBN 978-91-576-8540-7
eISBN 978-91-576-8541-4
[Doctoral thesis]

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Amino acids have been regarded as potential plant nitrogen sources for more than a century. Some amino acids have been shown to support growth while others have growth-retarding effects. The D-isomers with notably adverse effects on plants’ growth and development include D-serine and D-alanine. Recently, D-serine has been recognised as an endogenous ligand of receptor channels mediating calcium fluxes in plants, but otherwise little is known about endogenous roles of D-amino acids in plants.
In the studies underlying this thesis, the negative responses to D-serine and D-alanine were converted to positive effects in Arabidopsis thaliana (Arabidopsis) plants by introducing either of two D-amino acid-metabolising enzymes. Transgenic Arabidopsis lines expressing either the D-serine dehydratase (dsdA) gene from Escherichia coli or the D-amino acid oxidase (DAO1) gene from Rhodotorula gracilis grew with otherwise toxic D-amino acids as the sole nitrogen source. I also expressed a transporter specific for D-amino acids, which further increased the transgenic plants’ growth with D-serine as sole nitrogen source. Hence, both assimilation and uptake restrictions can limit plant growth on D-amino acids. The growth of transgenic lines on D-serine or D-alanine provides an unambiguous and highly visible phenotype, which is essential for a selectable marker. Thus, expressing of either the dsdA or DAO1 genes generated transformants that are easy to screen. Furthermore, the DAO1 gene can be readily used for either positive or negative selection, depending on the substrate, thus it provides a unique conditional, substrate-dependent positive/negative selectable marker for plant transformation.

In summary, the presented work demonstrates that introducing the ability to catalyse a single metabolic step can allow plants to exploit an otherwise inaccessible or toxic form of organic nitrogen, and provides a versatile marker based on nitrogen nutrition for selecting transgenic plants. A possible role for D-serine in plants’ touch response is also reviewed in the thesis.

Authors/Creators:Forsum, Oskar
Title:On plant responses to D-amino acids
Subtitle:features of growth, root behaviour and selection for plant transformation
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2 March 2016
Depositing date:2 March 2016
Number of Pages:75
IForsum O, Svennerstam H, Ganeteg U, Nasholm T (2008) Capacities and constraints of amino acid utilization in Arabidopsis. New Phytologist 179 (4),1058-1069.
IIErikson O, Hertzberg M, Nasholm T (2005) The dsdA gene from Escherichia coli provides a novel selectable marker for plant transformation. Plant Molecular Biology 57 (3),425-433.
IIIErikson O, Hertzberg M, Nasholm T (2004) A conditional marker gene allowing both positive and negative selection in plants. Nature Biotechnology 22 (4),455-458.
Place of Publication:Umeå
Publisher:Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8540-7
ISBN for electronic version:978-91-576-8541-4
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F30 Plant genetics and breeding
F Plant production > F61 Plant physiology - Nutrition
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Cell Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 107 Other Natural Sciences > Other Natural Sciences
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 209 Industrial Biotechnology > Bioengineering Equipment
Agrovoc terms:amino acids, arabidopsis thaliana, plant response, nitrogen, nutrient uptake, growth, roots, genetic markers, escherichia coli
Keywords:D-amino acid, metabolism, nitrogen, selectable markers, D-serine, GLR, Arabidopsis
Permanent URL:
ID Code:12997
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Ecology and Management
External funders:FORMAS
Deposited By: Mr Oskar Forsum
Deposited On:08 Feb 2016 14:11
Metadata Last Modified:10 Sep 2020 13:41

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