During evolution of multicellularity, cells differentiated to become specialized and interdependent. Multicellular organisms invented channels for nutrient exchange and communication between cells. Plants uniquely developed plasmodesmata, complex cell-cell connections traversing the cell wall. Roles ascribed to plasmodesmata include selective transport of signals, ions, metabolites, RNAs and proteins. Due to technical hurdles, composition, structure and regulation of plasmodesmatal conductance remain enigmatic. Genetic approaches to study plasmodesmata were hampered by lethality or redundancy. Novel technologies now set the stage for resolving roles of plasmodesmata in transport and signaling in an interdisciplinary approach. We will use proximity labeling proteomics to obtain plasmodesmatal composition, and PAINT and cryo-electron tomography (cryoET) for near atomic structures. Models of plasmodesmata will be built from bottom up and top down approaches and combined with quantitative assessment of plasmodesmatal activity. Novel biosensor approaches together with knock down by genome editing will permit quantitation of transport of the diverse cargo. Single cell sequencing helps fine-tuning mutant selection and targeting of subtypes. Four labs will join forces: highly recognized experts in biophysics and cryoET (WB), advanced imaging and developmental signaling (RS), high-end proteomics and lipidomics (WS), and interactomics, transporters and cutting-edge biosensor technology (WF).
We will iteratively address:
- systematic quantitative identification of components
- their localization and dynamics
- structures and molecular building blocks of diverse plasmodesmatal types
- transport and signaling mechanisms
We expect breakthrough discoveries and completely new understanding of plasmodesmatal function and evolution. Since plasmodesmata play key roles in nutrient allocation and virus spread, we lay the basis for novel biotech solutions in agriculture.
Our research team around Manuel Miras at the Heinrich Heine University Düsseldorf has identified 20 plasmodesmata core proteins. They compared the previously published plasmodesmatal proteomes of four different plant species (Fernandez-Calvino et al., 2011; Kraner et al., 2017; Leijon et al., 2018; Brault et al., 2019). 20 candidates were common to all four proteomes and may, thus, constutitute plasmodesmata core proteins. The manuscript by Miras et al. is submitted. The list of all analyzed proteins can be downloaded here.
Core Plasmodesmatal Proteome. The Venn diagram displays the number of proteins overlapping between four previously published plasmodesmatal proteomes.
Fernandez-Calvino, L., Faulkner, C., Walshaw, J., Saalbach, G., Bayer, E., Benitez-Alfonso, Y. and Maule, A., 2011. Arabidopsis plasmodesmal proteome. PloS one, 6(4), p.e18880.
Kraner, M.E., Müller, C. and Sonnewald, U., 2017. Comparative proteomic profiling of the choline transporter‐like1 (CHER 1) mutant provides insights into plasmodesmata composition of fully developed Arabidopsis thaliana leaves. The Plant Journal, 92(4), pp.696-709.
Leijon, F., Melzer, M., Zhou, Q., Srivastava, V. and Bulone, V., 2018. Proteomic analysis of plasmodesmata from populus cell suspension cultures in relation with callose biosynthesis. Frontiers in plant science, 9, p.1681.
Brault, M.L., Petit, J.D., Immel, F., Nicolas, W.J., Glavier, M., Brocard, L., Gaston, A., Fouché, M., Hawkins, T.J., Crowet, J.M. and Grison, M.S., 2019. Multiple C2 domains and transmembrane region proteins (MCTP s) tether membranes at plasmodesmata. EMBO reports, 20(8), p.e47182.
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