Molecule to Cell

 
 

 

In stark contrast to most animals, plants must grow and survive in a single location— some individuals can thrive for thousands of years. We are only beginning to learn how plants solve this incredible challenge. Parts of the answer seem to lie in their extremely efficient mechanisms of nutrient sensing, mining, regulation, and signal integration.
 
Plants must harvest CO2, water and 16 essential nutrients from the local environment to build organic molecules and ultimately construct a plant from scratch. The plant cell membrane plays a central role in this process, by controlling which compounds can enter or leave the cell. The membrane is also the base for many of the sensory and signaling functions of a cell. Relatively little is understood of how the plant cell membrane is organized and how membrane organization supports the processes of cell and tissue morphogenesis, signaling, nutrient acquisition and metabolic integration.
 
Also different from animal cells, plant cells are surrounded by a rigid cellulosic wall. The cell wall provides protection for each cell and also is the plant's primary load-bearing component—allowing some plants to grow into the largest free-standing biological structures on Earth. In exchange for their great benefits, the rigid cell walls constrain cell and tissue development. A central challenge in plant cell development is to understand how the cell organizes the construction of the cell wall to permit cell and tissue growth.
 
Wolf B. Frommer’s lab is a world leader in the field of uptake and release of nutrients in and from plant cells. His lab identified the first ammonium, amino acid, nucleobase and sucrose transporters and demonstrated their relevance for plant growth. The lab systematically studies the regulatory networks that enable the extraordinary efficiency of plants in nutrient uptake and transport of nutrients between cells. The lab pioneered the development and use of fluorescence resonance energy sensors to detect metabolites and monitor transport in real time. The lab is currently working on developing biosensors for plant hormones, long sought tools for studying hormonal control of development and physiology.
 
Communication within and between plant cells relies on direct interactions between proteins. Wolf B. Frommer’s lab, together with Sue Rhee’s lab, is systematically identifying the protein interactions between membrane proteins and the signaling proteins inside the cell.
 
David W Ehrhardt’s lab investigates the mechanisms of plant cell organization and morphogenesis. The lab has made major advances in visualizing and measuring the dynamic cellular machinery that organizes the cell and builds the cell wall, discovering new mechanisms that contribute to cytoskeletal organization and new functions for the cytoskeleton in organizing the cell membrane.
 
Together, David W Ehrhardt’s lab and Wolf B. Frommer’s lab are probing the organization of plant cell membranes by expressing and visualizing libraries of fluorescently tagged membrane and membrane-associated proteins.
 
Zhi Yong Wang’s lab unravels the mechanisms of brassinosteroid signaling, a means of cell-cell signaling that controls cell growth and patterns of tissue development and a model for steroid perception and signaling at the cell membrane. They recently filled in, for the first time in plants, the complete molecular chain of events from membrane receptor to nucleus.
 
Martin Jonikas’ lab and Arthur Grossman’s lab use green algae and model plants as a fast route to get to the basis of essential nutrient uptake and signaling. Martin Jonikas’ lab also develops new technologies to replace genes in algae, a major tool for identifying gene function currently absent in this model system.