title: Timing the switch to phototrophic growth: a possible role of GUN1.
abstract: In young Arabidopsis seedlings, retrograde signalling from plastids regulates the expression of photosynthesis-associated nuclear genes in response to the developmental and functional state of the chloroplasts. The chloroplast-located PPR protein GUN1 is required for signalling following disruption of plastid protein synthesis early in seedling development before full photosynthetic competence has been achieved. Recently we showed that sucrose repression and the correct temporal expression of LHCB1, encoding a light-harvesting chlorophyll protein associated with photosystem II, are perturbed in gun1 mutant seedlings. ( 1) Additionally, we demonstrated that in gun1 seedlings anthocyanin accumulation and the expression of the "early" anthocyanin-biosynthesis genes is perturbed. Early seedling development, predominantly at the stage of hypocotyl elongation and cotyledon expansion, is also affected in gun1 seedlings in response to sucrose, ABA and disruption of plastid protein synthesis by lincomycin. These findings indicate a central role for GUN1 in plastid, sucrose and ABA signalling in early seedling development.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Cottage
authors.forename: John C
authors.initials: JC
authors.lastname: Gray
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism; D008034:Lincomycin / Q000494:pharmacology; D052817:Phototrophic Processes / Q000187:drug effects* / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013395:Sucrose / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C519677:GUN1 protein, Arabidopsis; D045342:Light-Harvesting Protein Complexes; D011500:Protein Synthesis Inhibitors; D013395:Sucrose; D000040:Abscisic Acid; D008034:Lincomycin