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bioRxiv · 10.64898/2026.09.03.749221

Outer membrane 'PusCD' complexes coordinate phospho(inositol)lipid utilisation in plant Bacteroidota

Connolly, A. N.·Moushtaq, L.·Qian, P.·Brindley, A. A.·Scanlan, D. J.·van den Berg, B.·Hitchcock, A.·Lidbury, I.
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Abstract

Gram-negative bacteria belonging to the phylum Bacteroidota are prominent and ecologically important members of host-associated microbiomes. A feature of Bacteroidota species is the presence of diverse outer membrane TonB-dependent transporter and cognate surface exposed lipoprotein (TBDT-SLP) complexes. Many 'SusCD-like' TBDT-SLPs coordinate complex carbohydrate capture from the environment. Here, we show the model soil Bacteroidota species Flavobacterium johnsoniae synthesises two TBDT-SLP complexes (named PusCD1 and PusCD2) that are essential for growth on phosphatidylinositol, a member of an abundant lipid class within plant plasma membranes, as a phosphorus source. Structural characterisation of ligand-bound PusCD1 complex from F. johnsoniae membranes reveals a new binding mechanism for organophosphorus and broadens the known functional repertoire of this class of transporters. Diverse PusCD-like complexes are widespread among plant associated Bacteroidota, pointing to a major, previously unrecognised route for the recycling of organophosphorus compounds in the rhizosphere, with potential implications for engineering microbial-mediated phosphorus recovery from organic waste streams.

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Connolly, A. N., Moushtaq, L., Qian, P., Brindley, A. A., Scanlan, D. J., van den Berg, B., Hitchcock, A., Lidbury, I.. 2026-09-07. Outer membrane 'PusCD' complexes coordinate phospho(inositol)lipid utilisation in plant Bacteroidota. https://doi.org/10.64898/2026.09.03.749221

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