Gene Discovery in Aid of Plant Nutrition,
Human Health and Environmental Remediation
PI: Mary Lou Guerinot, Dartmouth College
Co-PIs: David J. Eide, University of Missouri
Jeffrey F. Harper, The Scripps Research Institute
David E. Salt, Purdue University
Julian I. Schroeder, University of California at San Diego
Michael Gribskov, University of California at San Diego
Uptake and translocation
of mineral nutrients in plants is essential for plant growth and
human nutrition. In spite of recent advances in identifying genes
involved in nutrient transport, the systems that control acquisition
of individual nutrients remain largely unknown. The major objective
of the proposed research is to identify gene networks that control
uptake and accumulation of a wide array of plant nutrients and
toxic metals. The approach makes use of recent technical advances
in inductively-coupled plasma atomic emission spectroscopy (ICP-AES)
which now permit the measurement of up to 72 different elements
in 35 seconds per sample. Identifying genes controlling solute
uptake and accumulation has significance for agriculture, human
health and the environment. For example, enhancing the ability
of a crop plant to mobilize soil nutrients should reduce the use
of fertilizers, thereby making agriculture more cost efficient
and less polluting. Because plants are the primary source of food
for humans, either directly or through animal feed, the nutritional
value of plants is of central importance to human health. The
most widespread nutritional problem in the world is iron deficiency.
Increasing the ability of plants to provide higher levels of minerals,
such as iron, will have a dramatic impact on human health. Furthermore,
understanding the pathways by which toxic metals accumulate in
plants will enable the engineering of plants to exclude toxic
metals and create healthier food sources, or to extract toxic
metals from the soil as a strategy to clean up polluted lands
and water.
The main aims of the
proposal are to:
1) Use bioinformatics
to identify genes that potentially encode transporters.
2) Use mRNA expression
profiling to identify genes that change expression in response
to nutrient deprivation or overfeeding.
3) Use nutrient profiling
to screen for mutant plants with abnormal element compositions.
ICP-AES will be used in a high-throughput strategy to determine
the relative element composition of approximately 50,000 "tagged"
mutagenized plants (Arabidopsis and maize).
4) Use yeast to obtain
functional predictions of plant orthologs. The primary approach
will be to conduct ICP-AES nutrient profiling of approximately
5,000 knockout lines of yeast.
5) Establish a Web
site to provide access to data sets and enhanced annotation of
genes.
6) Initiate collaborative
research focused on selected mutations that control accumulation
of Fe, Zn, Cu, Mn, K, Na, Ca, Ni, Se and Cd to demonstrate the
power of this novel approach.
7) Establish a program
to train undergraduate and graduate students in genomics, informatics
and plant molecular biological techniques.
8) Provide a service
to high school and college students who wish to test plants from
their local environment for levels of toxic and nutritional minerals.
This project will functionally
identify many important genes, including those that are involved
in:
1) nutrient mobilization
in the rhizosphere
2) cellular uptake
and efflux systems
3) subcellular compartmentalization
of solutes
4) the operation of
phloem and xylem translocation systems
5) central regulation
mechanisms
6) nutrient sensing
7) control of root
structure This functional genomic investigation will provide the
first integrated picture of the genes involved in a fundamental
feature of all living systems - the selective accumulation of
essential minerals.
