title: A role for jasmonates in the release of dormancy by cold stratification in wheat.
abstract: Hydration at low temperatures, commonly referred to as cold stratification, is widely used for releasing dormancy and triggering germination in a wide range of species including wheat. However, the molecular mechanism that underlies its effect on germination has largely remained unknown. Our previous studies showed that methyl-jasmonate, a derivative of jasmonic acid (JA), promotes dormancy release in wheat. In this study, we found that cold-stimulated germination of dormant grains correlated with a transient increase in JA content and expression of JA biosynthesis genes in the dormant embryos after transfer to 20 (o)C. The induction of JA production was dependent on the extent of cold imbibition and precedes germination. Blocking JA biosynthesis with acetylsalicylic acid (ASA) inhibited the cold-stimulated germination in a dose-dependent manner. In addition, we have explored the relationship between JA and abscisic acid (ABA), a well-known dormancy promoter, in cold regulation of dormancy. We found an inverse relationship between JA and ABA content in dormant wheat embryos following stratification. ABA content decreased rapidly in response to stratification, and the decrease was reversed by addition of ASA. Our results indicate that the action of JA on cold-stratified grains is mediated by suppression of two key ABA biosynthesis genes, TaNCED1 and TaNCED2.
authors.affiliation: Shandong Agricultural University, College of Agronomy, Taian, Shandong, China CSIRO Agriculture, Canberra ACT 2601, Australia.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Mass Spectrometry Facility, Research School of Biology, Australian National University, Canberra ACT 2601, Australia.
authors.forename: Thy T
authors.initials: TT
authors.lastname: Truong
authors.affiliation: CSIRO Agriculture, Canberra ACT 2601, Australia.
authors.forename: Jose M
authors.identifier: 0000-0001-7367-2199
authors.initials: JM
authors.lastname: Barrero
authors.affiliation: CSIRO Agriculture, Canberra ACT 2601, Australia.
authors.forename: John V
authors.initials: JV
authors.lastname: Jacobsen
authors.affiliation: Mass Spectrometry Facility, Research School of Biology, Australian National University, Canberra ACT 2601, Australia.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Hocart
authors.affiliation: CSIRO Agriculture, Canberra ACT 2601, Australia frank.gubler@csiro.au.
authors.forename: Frank
authors.identifier: 0000-0002-9392-942X
authors.initials: F
authors.lastname: Gubler
mesh_terms: D003080:Cold Temperature; D003517:Cyclopentanes / Q000378:metabolism*; D018525:Germination; D007532:Isoleucine / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D057445:Plant Dormancy; D014908:Triticum / Q000254:growth & development*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D007532:Isoleucine; C011006:jasmonic acid
keywords: Abscisic acid; acetylsalicylic acid; cold; dormancy; jasmonate; stratification; wheat.