Co-PIs: Erin Connolly (University of South Carolina), Leon Kochian and Miguel Piñeros (USDA-ARS/Cornell University), Michael Stowell (University of Colorado-Boulder), Julian Schroeder and Milton Saier (University of California, San Diego)
Plants need to take up nutrients from the soil and transport these nutrients to specialized cells throughout the whole plant. These nutrients are transported across plant cell membranes and organelle membranes inside of each plant cell. Transporters are proteins that mediate the passage of virtually every molecule and ion across plant cell membranes. Many natural variants of transport proteins have been shown to be important for key agronomic traits associated with plant growth and yield, and tolerance to abiotic and biotic stresses. However, the fundamental biochemical, functional, and structural characteristics of these proteins are largely unknown. To address these questions and the glaring need for new tools in this research area, we are establishing a new center called the Center for Research on Plant TransporterS (CROPS), devoted to the functional and structural characterization of plant transporters prioritized by their agronomic importance. This center will leverage an existing advanced research infrastructure to produce purified plant transporters on a large-scale and rapidly discover/generate novel single-domain antibodies that can be used as valuable tools and potentially transformative and enabling resources for the greater plant science community. In addition, CROPS will determine the molecular structures of key plant membrane transporters and their natural variants, providing a new framework for understanding their functions in the context of their in planta roles, underpinning agriculturally important traits in diverse crop species.
Our understanding of plant transporters has increased dramatically over the past quarter century. This has led to a growing awareness that plant transporters play important roles in many agronomic traits, such as efficient acquisition/use of water and nutrients and crop tolerance to adverse soil environments arising from salinity, acidity, and the presence of heavy metals. Natural genetic variation is the foundation for breeding a wide variety of agriculturally relevant traits. Understanding how genetic variation translates into transporter structural and functional changes is critical to provide for a more efficient exploitation of this variation in crop improvement. CROPS will focus on key questions regarding agronomic traits that relate to food security and sustainability under marginal conditions and human health/nutrition and food safety. Specifically, through external collaborations and internal expertise, CROPS will target key transporters including those involved in micronutrient acquisition, aluminum tolerance, phosphorous acquisition efficiency, nitrogen acquisition efficiency, salt tolerance and pathogen and insect resistance. As a first step, CROPS will establish an efficient pipeline based on proven technologies for the production of plant membrane transport resources for the plant scientific community. These resources include large quantities of purified plant transporter proteins, a powerful in vitro production platform for nanobodies, novel synthetic single-domain antibodies, and state-of-the-art structural determination techniques. CROPS has a strong commitment to providing access to all data and biological resources to the broader plant membrane transport community. Access to proteins, antibody reagents, and information about protein structure will be provided through a project website/database and by dissemination through long-term repositories. Specifically, all structural x-ray and EM structural data (GC and MS) will be deposited in the Protein Data Bank (http://www.pdb.org) and the EMDataBank (www.emdatabank.org). All plant and synthetic nanobody DNA sequences will be annotated and deposited in GenBank and Gramene. Plasmid constructs will be deposited in Addgene (www.addgene.org), a not-for-profit plasmid repository. With regard to outreach, CROPS will provide mechanisms for inviting the wider community to tap into its pipeline as a basis for their own research. Researchers will be invited to submit nominations for specific plant transporters of interest. Graduate students and postdocs will receive training and access to some of the most state-of-the-art techniques in rapid antibody (nanobody) evolution, membrane protein structural/functional biology, and molecular-based trait analysis for advancing independent careers. CROPS will have a strong emphasis on providing research training and laboratory experiences to high school and undergraduate students from underrepresented groups, with a focus on development of writing and presentation skills as well as mentoring students to take personal responsibility and gain scientific educational and project management skills.
