Sinorhizobium meliloti Controls Nitric Oxide–Mediated Post-Translational Modification of a Medicago truncatula Nodule Protein

Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about t...

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Bibliographic Details
Main Authors: Pauline Blanquet, Liliana Silva, Olivier Catrice, Claude Bruand, Helena Carvalho, Eliane Meilhoc
Format: Article
Language:English
Published: The American Phytopathological Society 2015-12-01
Series:Molecular Plant-Microbe Interactions
Online Access:https://apsjournals.apsnet.org/doi/10.1094/MPMI-05-15-0118-R
Description
Summary:Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about the molecular mechanisms responsible for NO effects in the legume-rhizobium interaction. Here, we investigate the contribution of the bacterial NO response to the modulation of a plant protein post-translational modification in nitrogen-fixing nodules. We made use of different bacterial mutants to finely modulate NO levels inside M. truncatula root nodules and to examine the consequence on tyrosine nitration of the plant glutamine synthetase, a protein responsible for assimilation of the ammonia released by nitrogen fixation. Our results reveal that S. meliloti possesses several proteins that limit inactivation of plant enzyme activity via NO-mediated post-translational modifications. This is the first demonstration that rhizobia can impact the course of nitrogen fixation by modulating the activity of a plant protein.
ISSN:0894-0282
1943-7706