RUI: Spatiotemporal mapping of the membrane trafficking networks involved in secretion and autophagy in the unicellular zygnematophyte, Penium margaritaceum

The goal of this research project is to provide a comprehensive examination of the membrane trafficking networks inside the cell involved in the processing of the extensive extracellular matrix (ECM) of Penium margaritaceum, a single-celled zygnematophyte, or algae, whose ancestors gave rise to land plants. This is important because at present, no detailed maps of the membrane trafficking network of Penium or any other zygnematophytes exist.

Membrane trafficking networks responsible for the production of the ECM were critical for ancient terrestrialization (movement from sea to land). Today, these networks are responsible for supporting zygnematophytes in major freshwater communities, including ephemeral blooms and biofilms. This project will construct structural models of the membranes inside the cell by using high resolution, electron microscopy analyses, and the functions of specific membrane components will be explained using targeted chemical and antibody agents.

This project will not only provide critical insight into the ECM secretion dynamics in plants and membrane trafficking events that were key in plant movement to land, but will also expand opportunities for Skidmore College undergraduates and local high school students to engage in a meaningful cell biology research program using new space and available equipment at the newly opened Center for Integrative Sciences (CIS). It will also include a unique training and mentoring program for a postdoctoral researcher that will involve participation in the research and preparation for a potential career at an undergraduate institution.

This project will investigate the structure and function of the subcellular machinery associated with the production of the extensive extracellular matrix of Zygnematophycean algae, the group of green algae most closely related and ancestral to land plants. The project will yield models that synthesize the architecture and function of the membrane trafficking networks involved with ECM secretion, cytokinesis, vacuolar dynamics and autophagy in the model unicellular zygnematophyte, Penium margaritaceum.

It will use multiple microscopy tools, tomography, immunolabeling and experimental analyses to acquire data for the construction of detailed maps and 3-D models of the trafficking networks. These will provide key insight into the rapid cell growth and associated hyper-secretory activity that many zygnematophytes exhibit when forming ephemeral blooms and biofilms.

It will elucidate modulations of these networks in cells exposed to various abiotic stressors and targeted chemical agents. This project will also provide significant insight into the unique furrow-cell plate system employed during cytokinesis and the evolution of the plant phragmoplast/cell plate. Finally, it will provide new information about vacuole- and autophagy-based compartments and their functional roles in zygnematophytes.

This research is funded by the Cellular Dynamics and Function cluster in the Division of Molecular and Cellular Biosciences in the Directorate of Biological Sciences.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.