PLEIOTROPIC REGULATORY LOCUS 1 （PRL1） Integrates the Regulation of Sugar Responses with Isoprenoid Metabolism in Arabidopsis  

作　　者：Ursula Flores-Perez Jordi Perez-Gil Marta Closa Louwrance R Wright Patricia Botella-Pavia Michael A. Phillips Albert Ferrer Jonathan Gershenzon Manuel Rodriguez-Concepcion 

机构地区：[1]Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB, Jordi Girona 18, 08034 Barcelona, Spain [2]Departament de Bioquimica i Biologia Molecular, Facultat de Farmacia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain [3]Department of Biochemistry, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany [4]Present address: Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom

出　　处：《Molecular Plant》2010年第1期101-112,共12页分子植物（英文版）

摘　　要：The biosynthesis of isoprenoids in plant cells occurs from precursors produced in the cytosol by the mevalonate （MVA） pathway and in the plastid by the methylerythritol 4-phosphate （MEP） pathway, but little is known about the mechanisms coordinating both pathways. Evidence of the importance of sugar signaling for such coordination in Arabi- dopsis thaliana is provided here by the characterization of a mutant showing an increased accumulation of MEP-derived isoprenoid products （chlorophylls and carotenoids） without changes in the levels of relevant MEP pathway transcripts, proteins, or enzyme activities. This mutant was found to be a new loss-of-function allele of PRL1 （Pleiotropic Regulatory Locus 1）, a gene encoding a conserved WD-protein that functions as a global regulator of sugar, stress, and hormone responses, in part by inhibition of SNFl-related protein kinases （SnRK1）. Consistent with the reported role of SnRK1 kinases in the phosphorylation and inactivation of the main regulatory enzyme of the MVA pathway （hydroxymethylglutaryl coenzyme-A reductase）, its activity but not transcript or protein levels was reduced in prll seedlings. However, the accumulation of MVA-derived end products （sterols） was unaltered in mutant seedlings. Sucrose supplementation to wild- type seedlings phenocopied the prll mutation in terms of isoprenoid metabolism, suggesting that the observed isoprenoid phenotypes result from the increased sugar accumulation in the prll mutant. In summary, PRL1 appears to coordinate isoprenoid metabolism with sugar, hormone, and stress responses.The biosynthesis of isoprenoids in plant cells occurs from precursors produced in the cytosol by the mevalonate （MVA） pathway and in the plastid by the methylerythritol 4-phosphate （MEP） pathway, but little is known about the mechanisms coordinating both pathways. Evidence of the importance of sugar signaling for such coordination in Arabi- dopsis thaliana is provided here by the characterization of a mutant showing an increased accumulation of MEP-derived isoprenoid products （chlorophylls and carotenoids） without changes in the levels of relevant MEP pathway transcripts, proteins, or enzyme activities. This mutant was found to be a new loss-of-function allele of PRL1 （Pleiotropic Regulatory Locus 1）, a gene encoding a conserved WD-protein that functions as a global regulator of sugar, stress, and hormone responses, in part by inhibition of SNFl-related protein kinases （SnRK1）. Consistent with the reported role of SnRK1 kinases in the phosphorylation and inactivation of the main regulatory enzyme of the MVA pathway （hydroxymethylglutaryl coenzyme-A reductase）, its activity but not transcript or protein levels was reduced in prll seedlings. However, the accumulation of MVA-derived end products （sterols） was unaltered in mutant seedlings. Sucrose supplementation to wild- type seedlings phenocopied the prll mutation in terms of isoprenoid metabolism, suggesting that the observed isoprenoid phenotypes result from the increased sugar accumulation in the prll mutant. In summary, PRL1 appears to coordinate isoprenoid metabolism with sugar, hormone, and stress responses.

关 键 词：Carbohydrate metabolism metabolic regulation secondary metabolism--terpenoids  isoprenoids  and carotenoids Arabidopsis. 

分 类 号：Q548[生物学—生物化学] Q943