Marchantia polymorpha as a simple platform for plant-based production of functional nanobodies

Recombinant proteins have transformative potential in biomedicine, but their production is often costly and carries contamination risks. Plants offer an attractive alternative, with low growth costs and reduced pathogen risk, yet their slow growth cycles limit their use for rapid protein engineering. Here, we establish Marchantia polymorpha , a genetically tractable liverwort with a short life cycle, as a new platform for recombinant protein production. Using stable Agrobacterium-mediated transformation, we expressed an anti-mCherry nanobody fused to the fluorescent protein mTurquoise2 with different purification tags. Expression levels reached up to ∼120 µg/g fresh weight, and nanobody functionality was validated through a microscopy-based bead-binding assay. This yield rivals that of established systems such as Nicotiana benthamiana . Our results position M. polymorpha as a scalable, safe, and efficient chassis for protein engineering, with broad potential for applications in synthetic biology. This work opens the door to exploiting liverwort biotechnology for fast, cost-effective, and biosafe production of valuable recombinant proteins.