title: Elevated CO2 decreases the response of the ethylene signaling pathway in Medicago truncatula and increases the abundance of the pea aphid.
abstract: The performance of herbivorous insects is greatly affected by plant nutritional quality and resistance, which are likely to be altered by rising concentrations of atmospheric CO2 . We previously reported that elevated CO2 enhanced biological nitrogen (N) fixation of Medicago truncatula, which could result in an increased supply of amino acids to the pea aphid (Acyrthosiphon pisum). The current study examined the N nutritional quality and aphid resistance of sickle, an ethylene-insensitive mutant of M. truncatula with supernodulation, and its wild-type control A17 under elevated CO2 in open-top field chambers. Regardless of CO2 concentration, growth and amino acid content were greater and aphid resistance was lower in sickle than in A17. Elevated CO2 up-regulated N assimilation and transamination-related enzymes activities and increased phloem amino acids in both genotypes. Furthermore, elevated CO2 down-regulated expression of 1-amino-cyclopropane-carboxylic acid (ACC), sickle gene (SKL) and ethylene response transcription factors (ERF) genes in the ethylene signaling pathway of A17 when infested by aphids and decreased resistance against aphids in terms of lower activities of superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO). Our results suggest that elevated CO2 suppresses the ethylene signaling pathway in M. truncatula, which results in an increase in plant nutritional quality for aphids and a decrease in plant resistance against aphids.
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.|Graduate School, Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Yuefei
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Xianghui
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.|Research Network of Global Change Biology, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.
authors.forename: Wenhao
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.|Research Network of Global Change Biology, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Ge
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001042:Aphids; D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology*; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005838:Genotype; D017752:Greenhouse Effect; D006790:Host-Parasite Interactions; D046913:Medicago truncatula / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D052585:Phloem / Q000187:drug effects / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; D002245:Carbon Dioxide; C036216:ethylene; D009584:Nitrogen
keywords: Acyrthosiphon pisum (pea aphid); Medicago truncatula; elevated CO2; ethylene; nitrogen (N) metabolism; resistance
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