title: Pleiotropic regulatory locus 1 (PRL1) integrates the regulation of sugar responses with isoprenoid metabolism in Arabidopsis.
abstract: 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 Arabidopsis 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 SNF1-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 prl1 seedlings. However, the accumulation of MVA-derived end products (sterols) was unaltered in mutant seedlings. Sucrose supplementation to wild-type seedlings phenocopied the prl1 mutation in terms of isoprenoid metabolism, suggesting that the observed isoprenoid phenotypes result from the increased sugar accumulation in the prl1 mutant. In summary, PRL1 appears to coordinate isoprenoid metabolism with sugar, hormone, and stress responses.
authors.affiliation: Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB, Jordi Girona 18, Barcelona, Spain.
authors.forename: Ursula
authors.initials: U
authors.lastname: Flores-Pérez
authors.forename: Jordi
authors.initials: J
authors.lastname: Pérez-Gil
authors.forename: Marta
authors.initials: M
authors.lastname: Closa
authors.forename: Louwrance P
authors.initials: LP
authors.lastname: Wright
authors.forename: Patricia
authors.initials: P
authors.lastname: Botella-Pavía
authors.forename: Michael A
authors.initials: MA
authors.lastname: Phillips
authors.forename: Albert
authors.initials: A
authors.lastname: Ferrer
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gershenzon
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Concepción
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D009687:Nuclear Proteins; C492005:PRL1 protein, Arabidopsis; D013729:Terpenes; D002338:Carotenoids