Insight into the control of nodule immunity and senescence during Medicago truncatula symbiosis

Berrabah Fathi, Bernal Gautier, Elhosseyn Ait-Salem, El Kassis Cyrille, L'Horset Roxane, Benaceur Farouk, Wen Jiangqi, Mysore Kirankumar, Garmier Marie, Gourion Benjamin, Ratet Pascal, Gruber Véronique. 2023. Insight into the control of nodule immunity and senescence during Medicago truncatula symbiosis. Plant Physiology, 191 (1) : 729-746.

Url - jeu de données - Entrepôt autre : https://www.ncbi.nlm.nih.gov/nuccore/657386114 / Url - jeu de données - Entrepôt autre : https://www.ncbi.nlm.nih.gov/nuccore/66253045

Résumé : Medicago (Medicago truncatula) establishes a symbiosis with the rhizobia Sinorhizobium sp, resulting in the formation of nodules where the bacteria fix atmospheric nitrogen. The loss of immunity repression or early senescence activation compromises symbiont survival and leads to the formation of nonfunctional nodules (fix−). Despite many studies exploring an overlap between immunity and senescence responses outside the nodule context, the relationship between these processes in the nodule remains poorly understood. To investigate this phenomenon, we selected and characterized three Medicago mutants developing fix− nodules and showing senescence responses. Analysis of specific defense (PATHOGENESIS-RELATED PROTEIN) or senescence (CYSTEINE PROTEASE) marker expression demonstrated that senescence and immunity seem to be antagonistic in fix− nodules. The growth of senescence mutants on non-sterile (sand/perlite) substrate instead of sterile in vitro conditions decreased nodule senescence and enhanced defense, indicating that environment can affect the immunity/senescence balance. The application of wounding stress on wild-type (WT) fix+ nodules led to the death of intracellular rhizobia and associated with co-stimulation of defense and senescence markers, indicating that in fix+ nodules the relationship between the two processes switches from opposite to synergistic to control symbiont survival during response to the stress. Our data show that the immune response in stressed WT nodules is linked to the repression of DEFECTIVE IN NITROGEN FIXATION 2 (DNF2), Symbiotic CYSTEINE-RICH RECEPTOR-LIKE KINASE (SymCRK), and REGULATOR OF SYMBIOSOME DIFFERENTIATION (RSD), key genes involved in symbiotic immunity suppression. This study provides insight to understand the links between senescence and immunity in Medicago nodules.

Mots-clés Agrovoc : Fixation de l'azote, symbiose, Medicago truncatula, formation de nodosités, bactérie fixatrice de l'azote, formation atmosphérique, gène de fixation de l'azote

Classification Agris : H20 - Maladies des plantes
F60 - Physiologie et biochimie végétale

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

Agences de financement hors UE : Agence Nationale de la Recherche, Université Paris Cité, Université Paris-Saclay, National Science Foundation

Projets sur financement : (FRA) Mécanismes contrôlant la transition entre fixation d'azote et sénescence dans les nodosités symbiotiques de légumineuses, (FRA) Université de Paris

Auteurs et affiliations

• Berrabah Fathi, Université Amar Telidji (DZA) - auteur correspondant
• Bernal Gautier, Université Paris-Saclay (FRA)
• Elhosseyn Ait-Salem, Université Paris-Saclay (FRA)
• El Kassis Cyrille, Université Paris-Saclay (FRA)
• L'Horset Roxane, CIRAD-BIOS-UMR PVBMT (REU)
• Benaceur Farouk, Université Amar Telidji (DZA)
• Wen Jiangqi, Oklahoma State University (USA)
• Mysore Kirankumar, Oklahoma State University (USA)
• Garmier Marie, Université Paris-Saclay (FRA)
• Gourion Benjamin, Université de Toulouse (FRA)
• Ratet Pascal, Université Paris-Saclay (FRA)
• Gruber Véronique, Université Paris-Saclay (FRA) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/608012/)

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