| Workshop
goals. To establish a plan, utilizing the expertise from other
genome-sequencing projects, for a possible wheat genome-sequencing project.
The workshop will pose broader questions such as: Do we need to sequence
the wheat genome? What are the scientific needs for the sequence that
cannot be met with existing cereal sequence resources? Is it time to
sequence now? What genome should be sequenced (diploid or hexaploid)?
What type of sequence should be generated (whole genome shotgun, selected
BACs, etc)? What strategies could be used to yield the type of sequence
needed? What timetable should be followed for the next steps? How will
the broader community be engaged? A report will be published in hardcopy
and posted on pertinent websites before the next Plant and Animal Genome
meeting in January 2004.
Background.
- Wheat is the
most widely grown crop, comprising 17% of all cultivated land, a staple
of 40% of the world's population providing 20% of the calories consumed.
Wheat also provides approximately 55% of the worlds carbohydrates.
To meet human demands in 2050, grain production needs to increase
at an annual rate of 1.5+% on an area of land that will not increase
much beyond present levels. This implies that significant advances
in the understanding of the wheat plant and grain biology must occur
in order to increase absolute yield as well as protect the crop from
25% loss due to biotic (pests) and abiotic stress (heat, drought,
and salinity).
- Most of our
food comes from plants, wheat included, that have evolved through
the unique mechanism of polyploidy. The proposal to sequence the gene-rich
regions of wheat is the first of its kind to study the genome sequence
of a polyploid. This is only feasible in wheat because genetic resources
are available to isolate segments of interest.
- Lack of genome/gene-sequence
information and underinvestment in wheat genomics is adversely impacting
crop genetics and polyploidy research.
ÿ Although the wheat genome is large (16,000,000,000 base pairs,
five times the size of the human genome sequenced at a cost of $4,000,000,000),
recent research shows that the wheat genome consists of gene-poor
and gene-rich components. Sequencing of the gene-rich regions of the
wheat genome is feasible due to the abundance of cytogenetic, molecular,
and human resources.
- In 2002, wheat
scientists founded IGROW (International Genome Research on Wheat)
to promote wheat genomics. An IGROW workshop was held at the 10th
International Wheat Genetics Symposium, September 2003, in preparation
for the USDA/NSF/IGROW workshop, to engage the international community
and begin to develop a consensus on the strategy for sequencing of
the wheat genome. Over 500 scientists from 45 countries participated
in the meeting.
Outlook.
- Depending upon
the strategy, a wheat-sequencing project may cost $60,000,000-250,000,000
over 5 years, and 10 countries have an interest in participating in
the project.
- Scientists from
12 countries (Australia, Canada, China, Czech Republic, France, Germany,
India, Italy, Japan, South Africa, Switzerland, and the United Kingdom)
and groups in the USA have indicated their commitment to focusing
on certain regions of the genome, with the aim of joining their sequencing
efforts into a larger wheat genome-sequencing effort. This staged
approach builds on the resources already established by large investments
in the USA, as well as investments in other countries.
- It seems likely
that a BAC-based approach will be combined with a genome fragment-based
approach to determine the sequence of gene-rich regions of the wheat
genome. A sequence-ready BAC contig map of bread wheat, integrated
into the genetic and EST maps, would provide the basic framework for
the sequencing of gene-rich regions.
- Continued comparative
genomics utilizing the analysis of rice and Brachypodium
would significantly enhance the functional analysis of genes in wheat.
- Key outputs
from a major structure/function analysis of the wheat genome would
include the identification of genes and chromosome regions controlling
yield attributes, complex agronomic traits, disease resistance, quality
traits, domestication, ploidy, and ploidy-regulated gene expression.
[PDF]
Workshop
organizers. Dr. Bikram S. Gill (bsgill@ksu.edu),
Kansas State University, USA, and Dr. Rudi Appels, (rappels@murdoch.edu.au),
Murdoch University, Australia. |
