Due to public and regulatory restrictions, genetic containment technology is critical for research and development of transgenic trees in forestry. A multi-year field trial demonstrated that the RNAi-LFY construct successfully induces sexual sterility in 6K10 poplar (Populus alba) without visible effects on vegetative development. However, its limited number of replicates...
The Arabidopsis thaliana developmental promoters of WUSCHEL (WUS) and COLD SHOCK DOMAIN PROTEIN 3 (CSP3) were tested for their suitability as potential control elements for the Cre-Lox recombination system in poplar cells. To remove the integrated transgene after CRISPR machinery has modified the genome, timely control of Cre is required....
Epigenetic mechanisms are important for control of plant development, and may play a particularly important role in trees given their long life cycles and distinctive and stable tissue types. To help understand the role of epigenetics in tree development, we produced transgenic poplars with reduced activity of the DDM1 genes,...
Transgenic biotechnology holds enormous potential as a tool to address global food insecurity. Transgenic food crops have been shown to increase food availability and food system security by incorporating disease, pesticide and drought resistance. Production costs of transgenic crops are lower due to the reduced need for costly pesticides and...
The debate over GM crops is one of the most controversial issues of recent decades. The debate has many dimensions, including environmental impacts, benefits and risks to human health, intellectual property rights, adequacy of biosafety regulations, and fundamental ethical acceptability. The potential benefits of GM crops are numerous, including improved...
Transformation is a major bottleneck for genetic engineering and gene editing in forest tree species. This includes most genotypes of Populus and Eucalyptus, which are some of the world’s most widely-cultivated genera of plantation forest trees. To provide new tools for transformation, I tested the transcription factor-protein chimera consisting of...
To reduce the environmental impacts caused by gene flow from transgenic trees, reproductive sterility genes have been developed that use a floral regulatory element linked to a cell toxin. This results in dysfunction or ablation of floral tissues, causing sterility. However, floral promoters often permit low levels of expression in...
Chloroplast genomes of conifers are unusual in a
number of respects, including the possession of much
repetitive DNA. By studying the distribution and sequences
of dispersed repetitive DNA, I hoped to gain insight into
the mechanisms of chloroplast genome evolution.
I used restriction mapping and DNA sequencing to
characterize dispersed...
This dissertation is comprised of four studies on different elements of Populus biotechnology and genomic science: 1) growth improvement by recombinant DNA (rDNA) modification of gibberellin (GA) metabolism; 2) gene editing using zinc-finger nucleases (ZFNs); 3) induction of floral sterility by RNA interference (RNAi) of AGAMOUS (AG) gene homologs; and...
An impediment to use of exotic and bioengineered trees in many places is their propensity for spread by pollen and/or seeds. Our laboratory has been using gene editing to induce mutations in floral genes as means to impart stable and reliable genetic containment when this is desirable from social (markets,...