title: Nitrogen deficiency in barley (Hordeum vulgare) seedlings induces molecular and metabolic adjustments that trigger aphid resistance.
abstract: Agricultural nitrous oxide (N2O) pollution resulting from the use of synthetic fertilizers represents a significant contribution to anthropogenic greenhouse gas emissions, providing a rationale for reduced use of nitrogen (N) fertilizers. Nitrogen limitation results in extensive systems rebalancing that remodels metabolism and defence processes. To analyse the regulation underpinning these responses, barley (Horedeum vulgare) seedlings were grown for 7 d under N-deficient conditions until net photosynthesis was 50% lower than in N-replete controls. Although shoot growth was decreased there was no evidence for the induction of oxidative stress despite lower total concentrations of N-containing antioxidants. Nitrogen-deficient barley leaves were rich in amino acids, sugars and tricarboxylic acid cycle intermediates. In contrast to N-replete leaves one-day-old nymphs of the green peach aphid (Myzus persicae) failed to reach adulthood when transferred to N-deficient barley leaves. Transcripts encoding cell, sugar and nutrient signalling, protein degradation and secondary metabolism were over-represented in N-deficient leaves while those associated with hormone metabolism were similar under both nutrient regimes with the exception of mRNAs encoding proteins involved in auxin metabolism and responses. Significant similarities were observed between the N-limited barley leaf transcriptome and that of aphid-infested Arabidopsis leaves. These findings not only highlight significant similarities between biotic and abiotic stress signalling cascades but also identify potential targets for increasing aphid resistance with implications for the development of sustainable agriculture.
authors.affiliation: Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Gloria
authors.initials: G
authors.lastname: Comadira
authors.affiliation: Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Brwa
authors.initials: B
authors.lastname: Rasool
authors.affiliation: Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Barbara
authors.initials: B
authors.lastname: Karpinska
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Jenny
authors.initials: J
authors.lastname: Morris
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Verrall
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Hedley
authors.affiliation: Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Christine H
authors.initials: CH
authors.lastname: Foyer
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK rob.hancock@hutton.ac.uk.
authors.forename: Robert D
authors.identifier: http://orcid.org/0000-0001-5465-3814
authors.initials: RD
authors.lastname: Hancock
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects / Q000502:physiology*; D018533:Biomass; D002244:Carbon / Q000494:pharmacology; D002734:Chlorophyll / Q000378:metabolism; D016000:Cluster Analysis; D060467:Disease Resistance / Q000187:drug effects; D005740:Gases / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D001467:Hordeum / Q000187:drug effects / Q000235:genetics / Q000469:parasitology*; D009584:Nitrogen / Q000172:deficiency* / Q000378:metabolism / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D010788:Photosynthesis / Q000187:drug effects; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology*; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D064210:Secondary Metabolism / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism* / Q000469:parasitology*; D015398:Signal Transduction / Q000187:drug effects; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism / Q000469:parasitology; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome / Q000235:genetics
chemical_list: D005740:Gases; D010940:Plant Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D002734:Chlorophyll; D002244:Carbon; D009584:Nitrogen
keywords: Cross-tolerance; Myzus persicae; kinase cascades; metabolite profiles; nitrogen limitation; oxidative stress; sugar signalling.