Photobiological hydrogen production -- the use of photosynthesis to split water into hydrogen and oxygen -- presents an opportunity for efficient and large-scale solar biofuel development. One of the major challenges in this area is competition for reductant between the hydrogen-evolving hydrogenase enzyme and other metabolic pathways. In this work...
Streptococcus gordonii is a bacterial species that naturally colonizes the oral cavity of most healthy humans. It resides in the mouth as an adherent to dental surfaces and, with few exceptions, does not cause disease in individuals it inhabits. It possesses qualities that encourage its use as a vector to...
The production of barley (Hordeum vulgare L.) haploids by crossing with
H. bulbosum is a widely used tool in breeding and genetics. Certain barley
genotypes have low seed set in this interspecific cross, a phenomenon known
as partial incompatibility. Haploid production efficiency and gamete sampling
are important issues with the...
The investigations reported are based on two studies; the first
is concerned with the selection practiced for performance in one inbred
Angus and three inbred Hereford lines of cattle, the realized
responses, levels of inbreeding and associated performance, and
heritabilities of the performance traits.
Selection differentials for all performance traits...
Agrobacterium tumefaciens, the causative agent of crown gall
disease, does not readily infect commercial varieties of alfalfa (Medicago sativa). Cloned virulence genes from the megaplasmid pTiBo542 have
been shown to enhance Agrobacterium host range and infectivity on
dicotyledonous plants. To obtain a gene transfer system for commercial
alfalfa cultivars, an...
Stable expression of transgenes is required for commercial uses of genetically engineered trees. To better understand the stability of transgene expression under field conditions, we studied transgene expression and RNA interference (RNAi)-induced transgene suppression in 2,480 transgenic poplars (460 transgene insertion events) over three years. Stability of expression was assessed...
Experiments focusing on plant growth regulators’ concentrations and combination, mineral salt formulations and TDZ pretreatment formations were conducted to optimize in vitro shoot regeneration from leaf and petiole explants of 'Marion' blackberry. Optimum shoot formation was obtained when stock plants were incubated in TDZ pretreatment medium for three weeks before...
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...
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...
Understanding complex traits is a fundamental challenge in plant genetics and a prerequisite for molecular breeding. Tools for trait dissection are markers, maps, and quantitative trait locus (QTL) analysis. Marker-assisted selection (MAS) is an application that integrates these tools. In this thesis research, a new sequence-based marker was evaluated, maps...
Wheat (Triticum aestivum L.) is one of the most important crops in the world. It has been and continues to be one of the main sources of food for humans and animals. Although traditional wheat breeding has contributed greatly to the improvement of wheat both in productivity and biotic/abiotic stress...
Over the last four decades, the aquaculture sector especially in developing countries has experienced dramatic growth. The increase in aquaculture production is a combination of area expansion and technological change (enhanced strains, input of feed and fertilizer, and improved management). One example of such technological change is the selective breeding...
Tomato [Lycopersicon esculentum Mill.] plants are chilling sensitive and do not
naturally accumulate glycinebetaine (GB), a metabolite that functions as a stress
protectant in plants. While GB can increase tolerance of tomato plants to salt and
drought stresses, its effect on chilling tolerance has not been examined. To evaluate
whether...
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...
Limnology is undergoing a transition to high-throughput -omic analysis of freshwater
bacterial communities. An important first step in making the transition is to
characterize several genomes that can be used as references to guide metagenome
assembly and analysis. Here I characterize four new freshwater cyanobacterial
genomes, a pair of lake...
Crown gall disease is an agricultural problem caused by the soil-borne bacterium, Agrobacterium tumefaciens. A. tumefaciens oncogenes cause transformed plant cells to overproduce the hormones, auxin and cytokinin. High hormone levels cause unorganized plant cell growth resulting in a gall. Control of crown gall disease is difficult because after plant...