3-hydroxy-3-methylglutaryl coenzyme a reductase 1 interacts with NORK and is crucial for nodulation in Medicago truncatula

• Published in: The Plant cell Vol. 19; no. 12; p. 3974
• Main Authors: Kevei, Zoltán, Lougnon, Géraldine, Mergaert, Peter, Horváth, Gábor V, Kereszt, Attila, Jayaraman, Dhileepkumar, Zaman, Najia, Marcel, Fabian, Regulski, Krzysztof, Kiss, György B, Kondorosi, Adam, Endre, Gabriella, Kondorosi, Eva, Ané, Jean-Michel
• Format: Journal Article
• Language: English
• Published: United States 01.12.2007
• Subjects: Amino Acid Sequence; Enzyme Activation - drug effects; Gene Expression Regulation, Plant - drug effects; Hydroxymethylglutaryl CoA Reductases - genetics; Hydroxymethylglutaryl CoA Reductases - metabolism; Immunoprecipitation; In Situ Hybridization; Lovastatin - pharmacology; Medicago truncatula - genetics; Medicago truncatula - metabolism; Medicago truncatula - microbiology; Models, Genetic; Molecular Sequence Data; Mutation; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Binding; Protein Isoforms - chemistry; Protein Isoforms - genetics; Protein Isoforms - metabolism; Protein Structure, Tertiary; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Root Nodules, Plant - genetics; Root Nodules, Plant - metabolism; Root Nodules, Plant - microbiology; Sequence Homology, Amino Acid; Sinorhizobium meliloti - growth & development; Symbiosis; Two-Hybrid System Techniques
• ISSN: 1040-4651

NORK in legumes encodes a receptor-like kinase that is required for Nod factor signaling and root nodule development. Using Medicago truncatula NORK as bait in a yeast two-hybrid assay, we identified 3-hydroxy-3-methylglutaryl CoA reductase 1 (Mt HMGR1) as a NORK interacting partner. HMGR1 belongs to a multigene family in M. truncatula, and different HMGR isoforms are key enzymes in the mevalonate biosynthetic pathway leading to the production of a diverse array of isoprenoid compounds. Testing other HMGR members revealed a specific interaction between NORK and HMGR1. Mutagenesis and deletion analysis showed that this interaction requires the cytosolic active kinase domain of NORK and the cytosolic catalytic domain of HMGR1. NORK homologs from Lotus japonicus and Sesbania rostrata also interacted with Mt HMGR1, but homologous nonsymbiotic kinases of M. truncatula did not. Pharmacological inhibition of HMGR activities decreased nodule number and delayed nodulation, supporting the importance of the mevalonate pathway in symbiotic development. Decreasing HMGR1 expression in M. truncatula transgenic roots by RNA interference led to a dramatic decrease in nodulation, confirming that HMGR1 is essential for nodule development. Recruitment of HMGR1 by NORK could be required for production of specific isoprenoid compounds, such as cytokinins, phytosteroids, or isoprenoid moieties involved in modification of signaling proteins.