Alex Guyon

Mutualist-pathogen co-colonisation modulates phosphoinositide signatures at host intracellular interfaces: Nicotiana benthamiana plants expressing biosensors for PI4P and PI(4,5)P2. PI(4,5)P2 was tip-enriched at mutualist structures but evenly distributed around pathogen structures. PI4P was absent from pathogen extrahaustorial membranes but present at invasive hyphae and mutualist interfaces. Co-colonisation triggered PI4P recruitment at pathogen haustoria, and enhanced resistance to P. palmivora. Graphic by Alex Guyon.

Arbuscular mycorrhizal fungi boost plant resilience by remodelling the plant-pathogen membrane interface
Check-out the latest paper from @alexguyon.bsky.social & @dromius.bsky.social
📖 doi.org/10.1016/j.ce... in @cp-cellreports.bsky.social
News article www.slcu.cam.ac.uk/news/arbuscu...

Thank you!

Thanks very much, only possible thanks to your biosensors!

Flowers and mycorrhizal roots – closer than we think? Roots and flowers are formed at the extreme ends of plants and they differ in almost every aspect of their development and function; even so, they exh…

More similarities between flower development and mutualist accommodation seem to keep emerging. www.sciencedirect.com/science/arti...

That's a cool parallel, I guess the cell biology of the pollen vegetative cell containing the sperm cells is analogous to a root cortex cell containing an arbuscule. Did you see the PI(4,5)P2 biosensor localising to subdomains of the peri-germ cell membrane, similar to the arbuscule tips?

8/ TL;DR:
✅ Phosphoinositide signatures at plant-microbe interfaces are dynamic
✅ Mutualist colonisation reshapes pathogen interface identity
✅ This shift correlates with enhanced resistance, suggesting membrane identity may influence infection outcome.

8/ Beyond just documenting these dynamics, our work asks:
🌱 Can we rethink host-pathogen “specialised” membranes as dynamic, context-dependent landscapes?
🔬 Are immune evasion strategies vulnerable in complex microbial environments?

7/ So what's going on? We propose that PI4P exclusion from haustoria is a pathogen-driven strategy, likely involving secreted effectors.
But during AM symbiosis, trafficking to arbuscules may override this, forcing the pathogen into an interface it didn’t design.

6/ Even more: co-colonisation enhances resistance to P. palmivora. Mutualist presence seems to rewire the pathogen interface.

5/ But here's the twist, during co-colonisation, haustoria begin recruiting PI4P
That’s a fundamental shift in membrane identity. And yes - we observed single plant cells simultaneously harbouring both an arbuscule and a haustorium!

4/Watch it in action! Here’s PI(4,5)P₂ (via biosensor P24Y) tracking fungal growth during AM symbiosis. Captured using @jenmcgaley.bsky.social‘s AMSlide.

3/ In single infections:
• PI(4,5)P₂ is tip-enriched in arbuscules but uniform around haustoria. Each interaction has a distinct membrane fingerprint.
• PI4P is present at the periarbuscular membrane of the mutualist but absent from haustoria of the pathogen.

2/ Phosphoinositides (PIPs) are key lipids that define membrane identity. We visualised PI(4,5)P₂ and PI4P biosensors from @yvonjaillais.bsky.social in Nicotiana benthamiana during root colonisation by a mutualist AM fungus - F. mosseae and a pathogen - P. palmivora. www.biorxiv.org/content/10.1...

1/🚨 New preprint alert! Can mutualists and pathogens co-colonise the same living plant cell and what does that do to the plant membranes that surround these microbes?

Excitingly, we also made it on the cover of the current issue of @theplantjournal.bsky.social with some of my #microscopy images checking for #immunofluorescence signal of FLAG-tagged cytochrome c6A in #chlamydomonas!

Intracellular pathogens can form extensive hyphal structures. Here, the pathogen Phytophthora palmivora (magenta) produces invasive hyphae in a living epidermal cell of a Nicotiana root. The plant surrounds the invader by an 'extra-invasive hyphal membrane' (yellow)📸 @alexguyon.bsky.social

Preprint! w/ C. Strullu-Derrien,R.Wightman,L.P.McDonnell, G.Evans,F.Fercoq,P.Kenrick & A.Ferrari

An ancient plant symbiotic fungus with distinct features identified through advanced fluorescence & Raman imaging

@slcuplants.bsky.social @nhm-london.bsky.social Cambridge Graphene Centre @mnhn.fr

We are thrilled to have been awarded a silver-gilt medal at our first Chelsea Flower Show! 🪻

An enormous thank you to everyone who contributed to this success - @eng.cam.ac.uk, Darwin Nurseries and Oakington Garden Centre!

#RHSChelsea @cambridgeuni.bsky.social

Great to see this out in the wild now!

Hi all, finally got around to making a Bluesky account. Looking forward to seeing all the cool work here and sharing some of my own!

Great start to the final day of #ICIPS2025 with a talk by @dromius.bsky.social showcasing the work of @davidjhoey.bsky.social about genetic control of marchantia reproductive strategies