ER-across the line: the function of the ER in plant intercellular communication

Objectif

The endoplasmic reticulum (ER) is central to cellular function, driving protein synthesis, lipid metabolism, and signaling. In most organisms, the ER is confined within individual cells. In plants, however, the ER takes an extraordinary form, defying cell boundaries as it stretches across the cell wall through plasmodesmata (PD) communication bridges. PD are indispensable for plant life. They control molecular flux between cells and are decisive for development, environmental adaptation, and defence signalling.
Although the ER association with PD has been known for decades, its role in cell-cell communication remains an enigma. Worse, the ER is mostly regarded as a passive element of intercellular signalling. The ER exists as an intercellular continuum, yet to this day, we don’t know what function this unique topology serves in cell-cell information exchange. How does the ER support plant multicellularity and integration of responses across tissues?
Our group recently reopened this question with two pioneering studies, pointing to the ER as an active player in intercellular signalling. With the ER-CONNECT project, I offer a conceptual shift by proposing that the ER is not a passive bystander but a key regulator and executor of plant cell-cell communication. Combining molecular dynamics, ultra-high-resolution imaging, and molecular cell biology, I will determine the ER's function with three specific aims:
1. Define how ER-embedded machinery controls cell-cell trafficking from within PD
2. Determine the function of cortical ER near PD in creating privileged zones for targeted molecular exchange
3. Establish whether the ER itself provides a direct route for molecular transport across cells
By uncovering how the ER underpins intercellular signalling, ER-CONNECT will resolve a long-standing question in plant biology and pioneer a new field of research on ER-mediated communication with broad relevance to how multicellular organisms coordinate responses across tissues