title: Epigenetic variation in plant responses to defence hormones.
abstract: OBJECTIVE
  There is currently much speculation about the role of epigenetic variation as a determinant of heritable variation in ecologically important plant traits. However, we still know very little about the phenotypic consequences of epigenetic variation, in particular with regard to more complex traits related to biotic interactions.
  
  
  METHODS
  Here, a test was carried out to determine whether variation in DNA methylation alone can cause heritable variation in plant growth responses to jasmonic acid and salicylic acid, two key hormones involved in induction of plant defences against herbivores and pathogens. In order to be able to ascribe phenotypic differences to epigenetic variation, the hormone responses were studied of epigenetic recombinant inbred lines (epiRILs) of Arabidopsis thaliana - lines that are highly variable at the level of DNA methylation but nearly identical at the level of DNA sequence.
  
  
  RESULTS
  Significant heritable variation was found among epiRILs both in the means of phenotypic traits, including growth rate, and in the degree to which these responded to treatment with jasmonic acid and salicylic acid. Moreover, there was a positive epigenetic correlation between the responses of different epiRILs to the two hormones, suggesting that plant responses to herbivore and pathogen attack may have a similar molecular epigenetic basis.
  
  
  CONCLUSIONS
  This study demonstrates that epigenetic variation alone can cause heritable variation in, and thus potentially microevolution of, plant responses to defence hormones. This suggests that part of the variation of plant defences observed in natural populations may be due to underlying epigenetic, rather than entirely genetic, variation.
authors.affiliation: Institute of Plant Sciences, University of Bern, Switzerland. vit.latzel@ips.unibe.ch
authors.forename: Vít
authors.initials: V
authors.lastname: Latzel
authors.forename: Yuanye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kim
authors.initials: K
authors.lastname: Karlsson Moritz
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.forename: Oliver
authors.initials: O
authors.lastname: Bossdorf
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D018533:Biomass; D003517:Cyclopentanes / Q000494:pharmacology*; D019175:DNA Methylation; D004463:Ecology; D057890:Epigenomics; D035264:Flowers / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D007178:Inbreeding; D054883:Oxylipins / Q000494:pharmacology*; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D057865:Plant Immunity; D030821:Plants, Genetically Modified; D012098:Reproduction; D020156:Salicylic Acid / Q000494:pharmacology*; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; D020156:Salicylic Acid