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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-380 - Nitrogen Phosphotransferase (PTS-Ntr) Crosstalk with (p)ppGpp Stringent Response and sRNAs AbcR1/2 in Rhizobium leguminosarum

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Subcellular dynamics and signaling in host-microbe interactions

    Presenting Author(s)

  • OT

    Olivia Tjahjono

    University of Oxford
    OXFORD, UNITED KINGDOM

    • Author(s)

  • DS

    Denis Shutin

    University of Oxford
    Oxford, England, United Kingdom

  • BF

    Ben Field

    Luminy Genetique et de Biophysique des Plantes (LGBP) - Bioscience and Biotechnology Institute of Aix-Marseille BIAM
    Marseille, Provence-Alpes-Cote d'Azur, France

  • SC

    Sylvie Citerne

    French National Institute for Agriculture, Food, and Environment (INRAE)
    Paris, Ile-de-France, France

  • AT

    Andrej Tkacz

    University of Oxford
    Oxford, England, United Kingdom

  • JB

    Jani Bolla

    University of Oxford
    Oxford, England, United Kingdom

  • PP

    Philip Poole

    University of Oxford
    Oxford, England, United Kingdom

  • CS

    Carmen Sanchez Canizares

    Royal Society University Research Fellow
    University of Oxford
    Oxford, England, United Kingdom

The Nitrogen Phosphotransferase systems (PTSNtr) and stringent response are both highly conserved regulatory networks which enable bacteria to adapt to fluctuating nitrogen availability in the environment. In the nitrogen-fixing bacterium R. leguminosarum, these global regulators are important for survival in the rhizosphere and successful root colonisation of host plants. PTSNtr senses the nitrogen status of the cell and balances the carbon and nitrogen metabolism by utilising the output proteins PtsN and ManX. Meanwhile, the stringent response is modulated by a bifunctional synthetase/hydrolase protein RelA/SpoT Homolog, producing the alarmone (p)ppGpp that causes global transcriptional changes under cellular stresses, including amino acid starvation. Another actuator for nitrogen response is the small RNAs AbcR1/AbcR2, which silence the mRNAs of ABC transporters involved in amino acid uptake in the related rhizobial species Sinorhizobium. By measuring (p)ppGpp levels, amino acid transports, and AbcR1/2 transcriptions in various PTS-Ntr mutants, as well as confirming the interaction between PtsN and RelA via native mass spectrometry, our works help to elucidate the crosstalk between PTS-Ntr, stringent response, and sRNAs AbcR1/2 in regulating nitrogen uptake via ABC transporters Aap. During nitrogen stress, PtsN binds to RelA, inducing the synthesis of (p)ppGpp. This results in the downregulation of negative regulator AbcR1/2, allowing the increase of amino uptake via Aap.