title: Reactive oxygen and nitrogen species and glutathione: key players in the legume-Rhizobium symbiosis.
abstract: Several reactive oxygen and nitrogen species (ROS/RNS) are continuously produced in plants as by-products of aerobic metabolism or in response to stresses. Depending on the nature of the ROS and RNS, some of them are highly toxic and rapidly detoxified by various cellular enzymatic and non-enzymatic mechanisms. Whereas plants have many mechanisms with which to combat increased ROS/RNS levels produced during stress conditions, under other circumstances plants appear to generate ROS/RNS as signalling molecules to control various processes encompassing the whole lifespan of the plant such as normal growth and development stages. This review aims to summarize recent studies highlighting the involvement of ROS/RNS, as well as the low molecular weight thiols, glutathione and homoglutathione, during the symbiosis between rhizobia and leguminous plants. This compatible interaction initiated by a molecular dialogue between the plant and bacterial partners, leads to the formation of a novel root organ capable of fixing atmospheric nitrogen under nitrogen-limiting conditions. On the one hand, ROS/RNS detection during the symbiotic process highlights the similarity of the early response to infection by pathogenic and symbiotic bacteria, addressing the question as to which mechanism rhizobia use to counteract the plant defence response. Moreover, there is increasing evidence that ROS are needed to establish the symbiosis fully. On the other hand, GSH synthesis appears to be essential for proper development of the root nodules during the symbiotic interaction. Elucidating the mechanisms that control ROS/RNS signalling during symbiosis could therefore contribute in defining a powerful strategy to enhance the efficiency of the symbiotic interaction.
authors.affiliation: Interactions Plantes-Microorganismes et Santé Végétale, UMR CNRS 6192/INRA 1064/Université de Nice-Sophia Antipolis, 400 route des Chappes, BP 167, F-06903 Sophia-Antipolis, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pauly
authors.forename: Chiara
authors.initials: C
authors.lastname: Pucciariello
authors.forename: Karine
authors.initials: K
authors.lastname: Mandon
authors.forename: Gilles
authors.initials: G
authors.lastname: Innocenti
authors.forename: Alexandre
authors.initials: A
authors.lastname: Jamet
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Baudouin
authors.forename: Didier
authors.initials: D
authors.lastname: Hérouart
authors.forename: Pierre
authors.initials: P
authors.lastname: Frendo
authors.forename: Alain
authors.initials: A
authors.lastname: Puppo
mesh_terms: D005978:Glutathione / Q000502:physiology*; D046913:Medicago truncatula / Q000502:physiology*; D009586:Nitrogen Fixation / Q000502:physiology; D026361:Reactive Nitrogen Species / Q000502:physiology*; D017382:Reactive Oxygen Species; D012231:Rhizobium / Q000502:physiology; D016962:Sinorhizobium meliloti / Q000502:physiology*; D013559:Symbiosis / Q000502:physiology
chemical_list: D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D005978:Glutathione