IPD3 Controls the Formation of Nitrogen-Fixing Symbiosomes in Pea and Medicago Spp

• Published in: Molecular plant-microbe interactions Vol. 24; no. 11; pp. 1333 - 1344
• Main Authors: Ovchinnikova, Evgenia, Journet, Etienne-Pascal, Chabaud, Mireille, Cosson, Viviane, Ratet, Pascal, Duc, Gerard, Fedorova, Elena, Liu, Wei, Camp, Rik Op den, Zhukov, Vladimir, Tikhonovich, Igor, Borisov, Alexey, Bisseling, Ton, Limpens, Erik
• Format: Journal Article
• Language: English
• Published: United States APS Press 01.11.2011; American Phytopathological Society; The American Phytopathological Society
• Subjects: bacteria; Base Sequence; Biochemistry, Molecular Biology; Cell Nucleus - metabolism; Cloning, Molecular; Cyclops; Cytokinins; Data processing; dependent protein-kinase; DNA Primers; erf transcription factor; genes sym33; Genes, Plant; hosts; Infection; intracellular accommodation; Legumes; Life Sciences; Lotus; Lotus corniculatus var. japonicus; Lotus japonicus; Medicago; Medicago - genetics; Medicago - microbiology; Medicago - physiology; Medicago truncatula; Microscopy, Confocal; mutants; mycorrhizae; Mycorrhizae - physiology; n-2-fixing symbiosomes; Nitrogen Fixation; Nodules; peas; peribacteroid membrane; Pisum sativum; Pisum sativum - genetics; Pisum sativum - microbiology; Pisum sativum - physiology; Plants, Genetically Modified; Polymerase Chain Reaction; root-nodules; Signal transduction; Symbiosis; symbiotic nodule development; truncatula roots; rhizobial bacteria; cell; symbiosome; nitrogen fixing symbiosis
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi-01-11-0013

A successful nitrogen-fixing symbiosis requires the accommodation of rhizobial bacteria as new organelle-like structures, called symbiosomes, inside the cells of their legume hosts. Two legume mutants that are most strongly impaired in their ability to form symbiosomes are sym1/TE7 in Medicago truncatula and sym33 in Pisum sativum. We have cloned both MtSYM1 and PsSYM33 and show that both encode the recently identified interacting protein of DMI3 (IPD3), an ortholog of Lotus japonicus (Lotus) CYCLOPS. IPD3 and CYCLOPS were shown to interact with DMI3/CCaMK, which encodes a calcium- and calmodulin-dependent kinase that is an essential component of the common symbiotic signaling pathway for both rhizobial and mycorrhizal symbioses. Our data reveal a novel, key role for IPD3 in symbiosome formation and development. We show that MtIPD3 participates in but is not essential for infection thread formation and that MtIPD3 also affects DMI3-induced spontaneous nodule formation upstream of cytokinin signaling. Further, MtIPD3 appears to be required for the expression of a nodule-specific remorin, which controls proper infection thread growth and is essential for symbiosome formation.