Tunnel mission: Plant virus movement through plasmodesmata

Abstract

Plasmodesmata (PD) constitute the symplastic pathway that allows plant viruses to spread locally and systemically through their hosts despite the barrier of the cell wall. Cell-to-cell transport through PD comprises an important bottleneck during infection as viruses are in a race against plant systemic defence responses. We are interested in the molecular details of this transport process, including how viral genomes are recruited for transport and how viruses interact with PD to manipulate them for transport. We have developed a live cell RNA imaging system, based on the inactivated bacterial endonuclease Csy4 (Cas6f), which is sensitive enough to observe viral genomes inside PD for the first time (Burnett et al. 2025). By itself, accessibility of viral RNAs within PD to Csy4 binding provides new insights into the cell-to-cell mobile ribonucleoprotein complexes. We have also used Csy4 RNA imaging to study viral movement complementation and constructed ‘self-tracking’ viruses expressing the reporter system in cis. These approaches facilitate new ways to study the links between virus replication and movement through PD. We are now developing orthogonal systems to enable simultaneous imaging of different viral RNAs inside plasmodesmata during co-infection or the establishment at the single cell level of viral superinfection exclusion.

References

Burnett et al. (2025) Live-cell RNA imaging with the inactivated endonuclease Csy4 enables new insights into plant virus transport through plasmodesmata. PLoS Pathog, https://doi.org/10.1371/journal.ppat.1013049(link is external)

Monsion et al. (2018) Efficient detection of long dsRNA in vitro and in vivo using the dsRNA binding domain from FHV B2 protein. Front Plant Sci, https://doi.org/10.3389/fpls.2018.00070(link is external)

Tilsner et al. (2013). Replication and trafficking of a plant virus are coupled at the entrances of plasmodesmata. J Cell Biol, https://doi.org/10.1083/jcb.201304003(link is external)