Accumulation of secondary metabolites in healthy and diseased barley, grown under future climate levels of CO2, ozone and temperature.
Plants produce secondary metabolites promoting adaptation to changes in the environment and challenges by pathogenic microorganisms. A future climate with increased temperature and CO2 and ozone levels will likely alter the chemical composition of plants and thereby plant-pathogen interactions. To investigate this, barley was grown at elevated CO2, temperature and ozone levels as single factors or in combination resembling future climatic conditions. Increased basal resistance to the powdery mildew fungus was observed when barley was grown under elevated CO2, temperature and ozone as single factors. However, this effect was neutralized in the combination treatments. Twenty-five secondary metabolites were putatively identified in healthy and diseased barley leaves, including phenylpropanoids, phenolamides and hydroxynitrile glucosides. Accumulation of the compounds was affected by the climatic growth conditions. Especially elevated temperature, but also ozone, showed a strong impact on accumulation of many compounds, suggesting that these metabolites play a role in adaptation to unfavorable growth conditions. Many compounds were found to increase in powdery mildew diseased leaves, in correlation with a strong and specific influence of the climatic growth conditions. The observed disease phenotypes could not be explained by accumulation of single compounds. However, decreased accumulation of the powdery mildew associated defense compound p-coumaroylhydroxyagmatine could be implicated in the increased disease susceptibility observed when barley was grown under combination of elevated CO2, temperature and ozone. The accumulation pattern of the compounds in both healthy and diseased leaves from barley grown in the combination treatments could not be deduced from the individual single factor treatments. This highlights the complex role and regulation of secondary metabolites in plants' adaptation to unfavorable growth conditions.
Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark; VILLUM research center for "Plant Plasticity", University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: bomi@plen.ku.dk.
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Mikkelsen
Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark; VILLUM research center for "Plant Plasticity", University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: ceo@plen.ku.dk.
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Olsen
Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark; VILLUM research center for "Plant Plasticity", University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: mlyn@plen.ku.dk.
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Lyngkjær
D000064:Acclimatization; D001203:Ascomycota / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism; D001467:Hordeum / Q000737:chemistry / Q000378:metabolism* / Q000382:microbiology; D010126:Ozone / Q000032:analysis* / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism; D013696:Temperature
D002245:Carbon Dioxide; D010126:Ozone
Biotic stress; Climatic stress; Hordeum vulgare; Hydroxynitrile glucosides; Phenolamides; Phenylpropanoids; Poaceae