Transcription of ENOD8 in Medicago truncatula Nodules Directs ENOD8 Esterase to Developing and Mature Symbiosomes
Open Access
- 1 April 2008
- journal article
- Published by Scientific Societies in Molecular Plant-Microbe Interactions®
- Vol. 21 (4), 404-410
- https://doi.org/10.1094/mpmi-21-4-0404
Abstract
In Medicago truncatula nodules, the soil bacterium Sinorhizobium meliloti reduces atmospheric dinitrogen into nitrogenous compounds that the legume uses for its own growth. In nitrogen-fixing nodules, each infected cell contains symbiosomes, which include the rhizobial cell, the symbiosome membrane surrounding it, and the matrix between the bacterium and the symbiosome membrane, termed the symbiosome space. Here, we describe the localization of ENOD8, a nodule-specific esterase. The onset of ENOD8 expression occurs at 4 to 5 days postinoculation, before the genes that support the nitrogen fixation capabilities of the nodule. Expression of an ENOD8 promoter-gusA fusion in nodulated hairy roots of composite transformed M. truncatula plants indicated that ENOD8 is expressed from the proximal end of interzone II to III to the proximal end of the nodules. Confocal immunomicroscopy using an ENOD8-specific antibody showed that the ENOD8 protein was detected in the same zones. ENOD8 protein was localized in the symbiosome membrane or symbiosome space around the bacteroids in the infected nodule cells. Immunoblot analysis of fractionated symbiosomes strongly suggested that ENOD8 protein was found in the symbiosome membrane and symbiosome space, but not in the bacteroid. Determining the localization of ENOD8 protein in the symbiosome is a first step in understanding its role in symbiosome membrane and space during nodule formation and function.Keywords
This publication has 36 references indexed in Scilit:
- How rhizobial symbionts invade plants: the Sinorhizobium–Medicago modelNature Reviews Microbiology, 2007
- Accumulation of extracellular proteins bearing unique proline-rich motifs in intercellular spaces of the legume nodule parenchymaProtoplasma, 2005
- Rapid analysis of legume root nodule development using confocal microscopyNew Phytologist, 2004
- Phosphorylation of Soybean Nodulin 26 on Serine 262 Enhances Water Permeability and Is Regulated Developmentally and by Osmotic SignalsPlant Cell, 2003
- Agrobacterium rhizogenes-Transformed Roots of Medicago truncatula for the Study of Nitrogen-Fixing and Endomycorrhizal Symbiotic AssociationsMolecular Plant-Microbe Interactions®, 2001
- Medicago truncatula ENOD11: A Novel RPRP-Encoding Early Nodulin Gene Expressed During Mycorrhization in Arbuscule-Containing CellsMolecular Plant-Microbe Interactions®, 2001
- Immunolocalization of PsNLEC-1, a Lectin-Like Glycoprotein Expressed in Developing Pea NodulesPlant Physiology, 1997
- Identification of a New Pea Gene, PsNlec1, Encoding a Lectin-like Glycoprotein Isolated from the Symbiosomes of Root NodulesPlant Physiology, 1996
- Studies on the Response of Carrot Cells to aSclerotinia sclerotiorumElicitor: Induction of the Expression of an Extracellular Glycoprotein mRNAMolecular Plant-Microbe Interactions®, 1996
- Rhizobium meliloti Nod factors elicit cell‐specific transcription of the ENOD12 gene in transgenic alfalfaThe Plant Journal, 1994