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Poplar Molecular Genetics and Genomics
(A. Groover)
Poplars occupy unique environmental niches, colonize sites after
disturbance, and provide habitat and food for a variety of wildlife.
Poplars are also used as windbreaks, for stream bank stabilization,
in remediation efforts, as a "biofuel" energy crop, and
as a source of pulp and chips by forest industry. Poplars are also
very amenable to advanced genetic analysis and are currently the
only forest tree with a completely sequenced
genome.
The Groover lab is establishing new molecular genetic tools that
identify and characterize individual poplar genes regulating wood
formation and crown architecture. For gene identification, a "gene
trapping" system has been established for poplars, which
identifies individual genes based on expression of the GUS reporter
gene. The sequence of the identified genes is determined by comparison
of DNA from the insertion site to the poplar genome sequence. The
gene trap lines are available for screening by other researchers,
and an Access database describing experiments to date is also available.
Contact A. Groover for more information.
This work is funded by competitive grants from the USDA NRI program.
The Groover lab is also studying the role of homeobox genes in
the regulation of secondary growth and wood formation. The maintenance
of a dividing, undifferentiated "stem cell" population
within the vascular cambium supplies the daughter cells that are
recruited into secondary vascular tissues in trees stems, including
secondary xylem (wood). Individual KNOX-class homeobox genes are
being characterized that regulate stem cell functions in the cambium,
and regulate genes that determine key cell wall properties including
lignin content. We have recently been funded by the Department of
Energy to determine the role of Class III HD Zip transcription factors
in regulating the relative ammounts of xylem and phloem during secondary
growth, towards better understanding the role of trees in carbon
sequestration and towards developing better biofuels applications.
The results from these studies should also give important insight
into the evolution of secondary growth in woody plants.
Conifer Molecular Genetics and Genomics
(D. Neale)
Coniferous trees play fundamental roles in forest ecosystems and provide
the bulk of raw materials for forest industry in the United States.
The Neale
lab is part of the UC Davis Department of Plant Sciences, and
works in collaboration with the Institute of Forest Genetics to develop
genomic science technologies to discover and understand the function
of genes controlling important traits in conifers. The program is
funded by IFG appropriations and considerable external funding from
USDA/NRI Plant Genome, DOE Agenda 2020, the National Science Foundation
Plant Genomics, and Weyerhaeuser Company.
Genes occur in various forms in nature called alleles, with each
allele having a unique DNA sequence and a unique influence on plant
growth and development. The different assemblage of alleles is thus
ultimately responsible for the genetic differences among individual
trees. We are using two primary strategies to identify and characterize
individual alleles of genes that influence traits in conifers ranging
from wood formation to resistance to pathogens. The first strategy
involves making molecular maps of tree genomes, and then seeking
correlations between inherited chromosomal regions and traits of
interest. We have used this method, know as Quantitative Trait Loci
Mapping, to scan the genomes of both loblolly pine and Douglas fir
for regions regulating both wood properties and adaptive traits.
In a second strategy, we have sequenced a large number of alleles
from expressed genes in conifer species (expressed sequence tags,
or ESTs) and developed Single Nucleotide Polymorphism (SNP) assays
for individual alleles of interest. We are now determining both
SNP genotypes and measuring traits of interest for large numbers
of trees. The final step in the process is to look for alleles of
individual genes that correlate (and thus regulate) traits of interest.
The information from this and other forest tree genetics projects
is available through Dendrome,
a forest tree genome database.
Allele Discovery
of Economic Pine Traits
Douglas-fir
Genome Project
Conifer Comparative
Genomics Project
White Pine
Blister Rust Resistance
Loblolly pine
Genome Project
Dendrome, A Forest Tree
Genome Database
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