Callose-Regulated Symplastic Communication Coordinates Symbiotic Root Nodule Development

Autor: Gaudioso-Pedraza, R, Beck, M, Frances, L, Kirk, P, Ripodas, C, Niebel, A, Oldroyd, GED, Benitez-Alfonso, Y, de Carvalho-Niebel, F
Přispěvatelé: Centre for Plant Sciences [Leeds], University of Leeds-Faculty of Biological Sciences-Institute of Integrative and Comparative Biology, Laboratoire des interactions plantes micro-organismes (LIPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Sainsbury Laboratory Cambridge, University of Cambridge [UK] (CAM), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Sainsbury Laboratory Cambridge University (SLCU), Leeds University : 110 French Laboratoire d'Excellence (Labex) TULIP post-doctoral grant 'Young Scientists for the Future', AgreenSkills fellowship : 2013609398, BBSRC DTP : BB/M011151/1, Royal Society, EPSRC : EF/M027740/1, Leverhulme Trust : RPG-2016-136, ANR COME-IN grant : ANR-14-CE35-0007-01, TULIP grant : ANR-10-LABX-41, European Project: 609398,EC:FP7:PEOPLE,FP7-PEOPLE-2013-COFUND,AGREENSKILLSPLUS(2014)
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Current Biology-CB
Current Biology-CB, Elsevier, 2018, 28 (22), pp.3562-3577.e6. ⟨10.1016/j.cub.2018.09.031⟩
Current Biology-CB, 2018, 28 (22), pp.3562-3577.e6. ⟨10.1016/j.cub.2018.09.031⟩
ISSN: 0960-9822
1879-0445
DOI: 10.1016/j.cub.2018.09.031⟩
Popis: International audience; The formation of nitrogen-fixing nodules in legumes involves the initiation of synchronized programs in the root epidermis and cortex to allow rhizobial infection and nodule development. In this study, we provide evidence that symplastic communication, regulated by callose turnover at plasmodesmata (PD), is important for coordinating nodule development and infection in Medicago truncatula. Here, we show that rhizobia promote a reduction in callose levels in inner tissues where nodules initiate. This downregulation coincides with the localized expression of M. truncatula beta-1,3-glucanase 2 (MtBG2), encoding a novel PD-associated callose-degrading enzyme. Spatiotemporal analyses revealed that MtBG2 expression expands from dividing nodule initials to rhizobia-colonized cortical and epidermal tissues. As shown by the transport of fluorescent molecules in vivo, symplastic-connected domains are created in rhizobia-colonized tissues and enhanced in roots constitutively expressing MtBG2. MtBG2-overexpressing roots additionally displayed reduced levels of PD-associated callose. Together, these findings suggest an active role for MtBG2 in callose degradation and in the formation of symplastic domains during sequential nodule developmental stages. Interfering with symplastic connectivity led to drastic nodulation phenotypes. Roots ectopically expressing beta-1,3-glucanases (including MtBG2) exhibited increased nodule number, and those expressing MtBG2 RNAi constructs or a hyperactive callose synthase (under symbiotic promoters) showed defective nodulation phenotypes. Obstructing symplastic connectivity appears to block a signaling pathway required for the expression of NODULE INCEPTION (NIN) and its target NUCLEAR FACTOR-YA1 (NF-YA1) in the cortex. We conclude that symplastic intercellular communication is proactively enhanced by rhizobia, and this is necessary for appropriate coordination of bacterial infection and nodule development.
Databáze: OpenAIRE
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