Are Histidine Kinases of Arbuscular Mycorrhizal Fungi Involved in the Response to Ethylene and Cytokinins?
2023
Mongès, Ayla | Yaakoub, Hajar | Bidon, Baptiste | Glévarec, Gaëlle | Héricourt, François | Carpin, Sabine | Chauderon, Lucie | Drašarová, Lenka | Spíchal, Lukáš | Binder, Brad, M | Papon, Nicolas | Rochange, Soizic | Laboratoire de Recherche en Sciences Végétales (LRSV) ; Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT) | SFR UA 4208 Interactions Cellulaires et Applications Thérapeutiques (ICAT) ; Université d'Angers (UA) | Biomolécules et biotechnologies végétales (BBV) ; Université de Tours (UT) | Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC) ; Université d'Orléans (UO)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Institute of Experimental Botany of the Czech Academy of Sciences (IEB / CAS) ; Czech Academy of Sciences [Prague] (CAS) | Palacky University Olomouc | The University of Tennessee [Knoxville] | LRSV-Evolution des Interactions Plantes-Microorganismes (LRSV-EIPM) ; Laboratoire de Recherche en Sciences Végétales (LRSV) ; Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT) | ANR-18-CE20-0001,Mycormones,Production, perception et transport de phytohormones par les champignons mycorhiziens à arbuscules(2018) | ANR-10-LABX-0041,TULIP,Towards a Unified theory of biotic Interactions: the roLe of environmental(2010)
International audience
Show more [+] Less [-]English. Signals are exchanged at all stages of the arbuscular mycorrhizal (AM) symbiosis between fungi and their host plants. Root-exuded strigolactones are well-known early symbiotic cues, but the role of other phytohormones as interkingdom signals has seldom been investigated. Here we focus on ethylene and cytokinins, for which candidate receptors have been identified in the genome of the AM fungus Rhizophagus irregularis. Ethylene is known from the literature to affect asymbiotic development of AM fungi, and in the present study, we found that three cytokinin forms could stimulate spore germination in R. irregularis. Heterologous complementation of a Saccharomyces cerevisiae mutant strain with the candidate ethylene receptor RiHHK6 suggested that this protein can sense and transduce an ethylene signal. Accordingly, its N-terminal domain expressed in Pichia pastoris displayed saturable binding to radiolabeled ethylene. Thus, RiHHK6 displays the expected characteristics of an ethylene receptor. In contrast, the candidate cytokinin receptor RiHHK7 did not complement the S. cerevisiae mutant strain or Medicago truncatula cytokinin receptor mutants and seemed unable to bind cytokinins, suggesting that another receptor is involved in the perception of these phytohormones. Taken together, our results support the hypothesis that AM fungi respond to a range of phytohormones and that these compounds bear multiple functions in the rhizosphere beyond their known roles as internal plant developmental regulators. Our analysis of two phytohormone receptor candidates also sheds new light on the possible perception mechanisms in AM fungi.
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