Chloroplast DNA (cpDNA) variability and phylogeny were
studied via analysis of restriction site mutations and DNA
sequencing in a complex of three closely related species of
pines: Pinus radiata D. Don, P. attenuata Lemm., and
muricata D. Don. Genomic DNA from 384 trees representing
20 populations in the complex were...
Hybrid poplar plantations (Populus trichocarpa x Populus deltoides) are a relatively new feature on the landscape in the Pacific Northwest of the United States, and these plantations may soon include genetically engineered trees. Meanwhile, many wild poplar populations (Populus spp.) are highly degraded due in part to logging, dams, grazing,...
We evaluated genes previously identified from a large scale functional genomics screen for their potential value to help enhance carbon sequestration in planted trees. We used poplar as a model tree species because of its abundant genetic variation, ease of gene transfer, and availability of large databases for genomic, anatomical,...
We tested a synthetic bacterio-opsin (bO) gene derived from Halobacterium halobium for its effect on disease resistance in transgenic poplar hybrids, and assessed a genetic system for controlling expression of this gene. In tobacco the bO gene caused necrotic lesions similar to an induced hypersensitive response (HR), increased levels of...
To help understand the mechanisms of conifer chloroplast genome evolution, we characterized the nucleotide sequences of Douglas-fir (Pseudotsuga menziesiz) and
Monterey pine (Pinus radiata) chioroplast DNA that are associated with a length
mutation hotspot and inversion. The chloroplast DNA ofthese two conifers are
characterized by shared large inversions that are...
In order to better understand the evolutionary patterns revealed by molecular
markers, we studied genetic diversity and differentiation of populations and races of
Douglas-fir using randomly amplified polymorphic DNA (RAPD) markers of nuclear and
mitochondrial origin. We conducted a range-wide survey of RAPD diversity and
differentiation, and compared RAPDs and...
Vegetative propagation allows the amplification of selected genotypes for research,
breeding, and commercial planting. However, efficient in vitro regeneration and
genetic transformation remains a major obstacle to research and commercial
application in many plant species. Our aims are to improve knowledge of gene
regulatory circuits important to meristem organization, and...
Septoria canker remains the most important disease of poplars in intensively managed forest plantations. Genetic resistance has long been considered the best way to manage for this disease. Transgenic resistance mediated by RNA silencing against pathogens and pests (HIGS: host-induced gene silencing) has shown promise in other pathosystems but has...
Agrobacterium tumefaciens and Agrobacteriwn rhizogenes, the causal agents of crown gall disease and hairy root disease, are known for their ability to transfer part of their
DNA (the T-DNA) from the bacterial tumor-inducing (Ti) plasmid to the genome of the
host plant. Interest has focused on these bacteria because they...
Our goal was to develop knowledge that will enable insertion of foreign genes into Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees. This required improvement of a tissue culture system for producing adventitious shoots from cotyledons, and study of factors affecting gene delivery, expression, and analysis. Administering a short-duration, concentrated liquid pulse...