NSF PR 00-60 - September 21, 2000
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NSF Boosts Research for Understanding Structure and
Function of Complex Plant Genomes
The National Science Foundation (NSF) is providing
a boost to plant biology research through 16 new grants
totaling more than $48 million over the next 5 years.
The new research will contribute to a better understanding
of the structure and function of all plant genes,
including those from economically important crops
like maize (corn), wheat and rice. According to program
managers the research emphasis is on functional genomics
and tools. Many of the projects will build on the
research outcomes from the first two years of the
Plant Genome Research Program.
"This year's awards continue to add new and exciting
dimensions to the field of plant genome research,"
says Mary Clutter, NSF assistant director for biological
sciences. "The focus has been on functional genomics
research designed to understand, at the whole genome
scale, the functions of plant genes involved in such
fundamental processes as chloroplast biogenesis, plant
nutrition, host-pathogen interactions, and plant responses
to environmental stress signals. Many of these projects
make full and effective use of plant genome research
infrastructure developed by the past awards. I am
confident that the new awards along with the past
awards will make the progress needed to meet the goals
of the National Plant Genome Initiative, of which
this NSF program is a part."
As scientists move from model systems to the challenges
of studying the larger, more complex genomes found
in economically important crops such as maize and
wheat, it will be important to have specialized tools
for analyzing gene structure and function, plant biologists
say. For example, bread wheat has a huge genome that
is a combination of the individual genomes coming
from several progenitor plants. The smallest of these,
known as the D genome, carries most of the important
genes for bread wheat improvement. A project funded
at the University of California at Davis will use
a new fingerprinting method that should allow construction
of a physical map of the D genome, the largest genome
to be tackled to date. This part of the wheat genome
alone is more than two and half times the size of
the whole maize genome, and ten times the size of
the whole rice genome. In addition to providing much-needed
tools for wheat research, the outcomes of this project
could eventually be useful for mapping genes in other
large plant genomes.
An important outcome of plant genome research has been
the finding that some plant genomes have undergone
significant changes on a whole-genome scale during
evolution. A common change is an increase in the number
of chromosome copies in the nucleus, termed polyploidy.
Many agriculturally important plants like maize and
wheat are polyploid, and their history has had a profound
impact on their genomes. The outcome of work funded
at the University of Wisconsin at Madison will give
the first genome wide analysis of the impact of ploidy
in one model species (Arabidopsis,the mustard plant)
and two crop species (brassica and maize). Other widespread
agents of genomic diversity are transposable elements.
About 30 percent of the new genome is thought to be
derived from these small, mobile pieces of DNA. Work
funded at the University of Georgia will examine the
rice genome to characterize all the different families
of elements present. The findings from this work should
give a complete picture of the elements from rice,
and point the way to characterizing this important
component of other larger cereal genomes.
The development of tools such as microarrays and tagged
mutants will allow scientists to begin to define the
functions of many of the genes in economically important
pathways and processes. New research under the latest
awards funded at the University of Florida will uncover
the genes involved in development of maize endosperm.
Endosperm, the starchy part of maize kernels, is an
important food source and also serves as a good basic
model for organ development in plants. In a related
project, research funded at the University of Oregon
will characterize the functions of genes needed to
build and maintain maize chloroplasts. Chloroplasts
are the compartments in plant cells where sunlight
is harvested and used to drive synthesis of sugars.
Plant pathogens also impact crop yield and basic plant
growth processes,but usually in a negative way. For
example, the root knot nematode worm (Meloidogyne
sps.) is an important pathogen of many economically
important crops such as soybean. North Carolina State
University researchers will take aim at understanding
the genes involved in the interaction between the
nematode and the plant during the infection process.
The outcome of this project has the potential to allow
development of novel nematode control strategies.
Research funded at Cornell University will tackle
another important plant pathogen, Pseudomonas syringae
pv. tomato, which causes bacterial speck disease in
tomato and related plants. This research will not
only increase our understanding of this specific disease,
but also the basic processes common to many pathogenic
interactions between plants and bacteria.
Researchers have found that many of the pathways involved
in building and maintaining plants involve cascades
of chemical signals known as plant hormones. If the
functions of these pathways are to be fully understood,
it will be necessary to gain a better understanding
of plant hormones and how they work, scientists believe.
Research funded at The University of Texas at Austin
will test a new screen for mutations affecting the
synthesis and action of one plant hormone known as
auxin. While some of these genes have already been
identified, this research will be the first to attempt
to collect a large number of mutants with defects
in all aspects of auxin biology.
For more information, see: http://www.nsf.gov/bio/pubs/awards/genome00.htm