Arabidopsis 2010 - Collaborative Research: Discovering Transporters for Essential Minerals and Toxic Ions in Plants

Plant growth, development, and survival depend on the uptake, translocation, and sorting of 15 essential nutrients and countless metabolites to specific organs, cells and intracellular compartments. However, it is not known how plants regulate and coordinate the complex network of long-distance and cellular transport patterns. The first complete genome sequence of a plant, large mutant collections, and extensive databases provide opportunities to generate new resources and tools to discover the functions of ~800 transporters in Arabidopsis. The bulk of unknown transporters are secondary active transporters. The major objectives of this project are to determine the ion specificity, the tissue and subcellular distribution, and the biological roles of 56 H+-coupled cation transporters, including the CaCA, CPA1, and CPA2 families. With the availability of genomic sequence and the identification of transport homologs through bioinformatic analyses, heterologous expression in yeast will be used to quickly delineate the function of the entire complement of H+-coupled cation transporters. Regulatory mechanisms will be determined by mutation of putative autoinhibitory domains. Transport in isolated membranes will be used to verify ion specificity of representative transporters. Tissue and subcellular distribution will be determined using promoter-reporter proteins expression in transgenic plants, and GFP-tagged transporters in a protoplast model. Biological and physiological functions of transporters will be analyzed using insertional knockout mutants. New methods and information resulting from the study will be distributed through a site at http://www.cbs.umn.edu/2010 with several updates each year. To assure that results and resources are available to the community, data will be depositied at TAIR and mutant Arabidopsis lines will be available through the ABRC after results are confirmed.

Transporters impact all life processes, including reproduction, metabolism, movement, and responses to hormonal and environmental stimuli, thus resources and information generated from this project will directly facilitate progress towards the goals of the 2010 project. Programs are in place to attract and provide opportunities for students, including under-represented minorities, to solve problems in health, agriculture, and the environment using experimental and bioinformatic approaches.