Plant lipid‐associated fibrillin proteins condition jasmonate production under photosynthetic stress |
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Authors: | Abir Youssef Yec’han Laizet Maryse A Block Eric Maréchal Jean‐Pierre Alcaraz Tony R Larson Dominique Pontier Joël Gaffé Marcel Kuntz |
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Institution: | 1. Laboratory Plastes et Différenciation Cellulaire, CNRS/Université Joseph Fourier, Grenoble, France;2. Laboratory Physiologie Cellulaire Végétale, CNRS/Université Joseph Fourier/INRA/CEA, Institut de Recherches en Technologies et Sciences pour le Vivant, 38054 Grenoble Cedex 9, France;3. CNAP, Department of Biology, University of York, York YO10 5YW, UK;4. Present address: Laboratoire Génome et Développement des Plantes, CNRS/Université de Perpignan Via Domitia/IRD, 52, Avenue P. Alduy, 66860 Perpignan, France.;5. Present address: LAPM – Institut Jean Roget, Faculté de Médecine, BP170, 38042 Grenoble Cedex 9, France. |
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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. |
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Keywords: | acclimation chloroplast jasmonic acid plastoglobule thylakoid triacylglycerol |
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