title: Plant lipid-associated fibrillin proteins condition jasmonate production under photosynthetic stress.
abstract: The role of a subfamily of lipid globule-associated proteins, referred to as plant fibrillins (FIB1a, -1b, -2), was determined using a RNA interference (RNAi) strategy. We show that Arabidopsis plants with reduced levels of these plastid structural proteins are impaired in long-term acclimation to environmental constraint, namely photooxidative stress imposed by high light combined with cold. As a result, their photosynthetic apparatus is inefficiently protected. This leads to the prevalence of an abnormal granal and stromal membrane arrangement, as well as higher photosystem II photoinhibition under stress. The visible phenotype of FIB1-2 RNAi lines also includes retarded shoot growth and a deficit in anthocyanin accumulation under stress. All examined phenotypic effects of lower FIB levels are abolished by jasmonate (JA) treatment. An atypical expression pattern of several JA-induced genes was observed in RNAi plants. A JA-deficient mutant was found to share similar stress phenotypic characteristics with FIB RNAi plants. We conclude a new physiological role for JA, namely acclimation of chloroplasts, and that light/cold stress-related JA biosynthesis is conditioned by the accumulation of plastoglobule-associated FIB1-2 proteins. Consistent correlative data suggest that this FIB effect is mediated by plastoglobule (and triacylglycerol) accumulation as the potential site for initiating the chloroplast stress-related JA biosynthesis.
authors.affiliation: Laboratory Plastes et Différenciation Cellulaire, CNRS/Université Joseph Fourier, Grenoble, France.
authors.forename: Abir
authors.initials: A
authors.lastname: Youssef
authors.forename: Yec'han
authors.initials: Y
authors.lastname: Laizet
authors.forename: Maryse A
authors.initials: MA
authors.lastname: Block
authors.forename: Eric
authors.initials: E
authors.lastname: Maréchal
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Alcaraz
authors.forename: Tony R
authors.initials: TR
authors.lastname: Larson
authors.forename: Dominique
authors.initials: D
authors.lastname: Pontier
authors.forename: Joël
authors.initials: J
authors.lastname: Gaffé
authors.forename: Marcel
authors.initials: M
authors.lastname: Kuntz
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D000071837:Fibrillins; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D054883:Oxylipins / Q000378:metabolism*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D034622:RNA Interference; D013312:Stress, Physiological
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D000071837:Fibrillins; D008840:Microfilament Proteins; D054883:Oxylipins; D045332:Photosystem II Protein Complex; C011006:jasmonic acid