| Title: | Endosymbiotic Sinorhizobium meliloti modulate Medicago root susceptibility to secondary infection via ethylene |
| Author(s): | Sorroche F; Walch M; Zou L; Rengel D; Maillet F; Gibelin-Viala C; Poinsot V; Chervin C; Masson-Boivin C; Gough C; Batut J; Garnerone AM; |
| Address: | "LIPM, Universite de Toulouse, INRA, CNRS, Castanet-Tolosan, France. Laboratoire IMRCP, UMR 5623 Universite de Toulouse, CNRS, Toulouse, France. GBF, Universite de Toulouse, INRA, Castanet-Tolosan, France" |
| ISSN/ISBN: | 1469-8137 (Electronic) 0028-646X (Linking) |
| Abstract: | "A complex network of pathways coordinates nodulation and epidermal root hair infection in the symbiotic interaction between rhizobia and legume plants. Whereas nodule formation was known to be autoregulated, it was so far unclear whether a similar control is exerted on the infection process. We assessed the capacity of Medicago plants nodulated by Sinorhizobium meliloti to modulate root susceptibility to secondary bacterial infection or to purified Nod factors in split-root and volatile assays using bacterial and plant mutant combinations. Ethylene implication in this process emerged from gas production measurements, use of a chemical inhibitor of ethylene biosynthesis and of a Medicago mutant affected in ethylene signal transduction. We identified a feedback mechanism that we named AOI (for Autoregulation Of Infection) by which endosymbiotic bacteria control secondary infection thread formation by their rhizospheric peers. AOI involves activation of a cyclic adenosine 3',5'-monophosphate (cAMP) cascade in endosymbiotic bacteria, which decreases both root infectiveness and root susceptibility to bacterial Nod factors. These latter two effects are mediated by ethylene. AOI is a novel component of the complex regulatory network controlling the interaction between Sinorhizobium meliloti and its host plants that emphasizes the implication of endosymbiotic bacteria in fine-tuning the interaction" |
| Keywords: | "Bacterial Proteins/metabolism Ethylenes/*metabolism Medicago truncatula/*microbiology Models, Biological Plant Diseases/*microbiology Plant Epidermis/microbiology Plant Root Nodulation Plant Roots/*microbiology Sinorhizobium meliloti/*physiology *Symbiosi;" |
| Notes: | "MedlineSorroche, Fernando Walch, Mathilda Zou, Lan Rengel, David Maillet, Fabienne Gibelin-Viala, Chrystel Poinsot, Verena Chervin, Christian Masson-Boivin, Catherine Gough, Clare Batut, Jacques Garnerone, Anne-Marie eng Research Support, Non-U.S. Gov't England 2019/05/07 New Phytol. 2019 Aug; 223(3):1505-1515. doi: 10.1111/nph.15883. Epub 2019 May 27" |
