Student Research Assistant University of Georgia Concord, North Carolina
Body of Abstract: The flowering dogwood tree, scientifically known as Cornus florida, is susceptible to powdery mildew, a fungus (Erysiphe pulchra) that infects plants causing stress which can lead to lower rates of floral budding. In flowering dogwood, the fungus requires a plant gene known as MLO for infection. Powdery mildew resistance is possible with the development of a successful gene transformation system and a plant tissue regeneration process, which combined will inactivate the MLO gene. This project will advance the research needed to achieve the regeneration of transgenic somatic embryos.
Currently, there is an established system for transforming embryogenic dogwood cultures via Agrobacterium. We will use Agrobacterium to integrate two genes into the dogwood’s nucleus. One gene codes for antibiotic resistance, known to be the selection gene. Another gene signals that transformation has occurred, known as the GUS reporter gene. The limiting component to continuous research is the successful regeneration and production of high-quality embryos from transgenic tissue culture systems. Using a physical means of the RITA® bioreactor temporary immersion system, we will conduct an experiment to improve embryo production and development. We will also conduct an experiment via a chemical means of Gibberellic acid (GA3). GA3 is a phytohormone that is involved in embryo development.
The improved regeneration process of the tissue cultures will allow the full development of healthy trees from somatic embryos. We can extend this research into CRISPR development. The newly adopted CRISPR process within the plant’s nucleus, made possible via Agrobacterium inserting the selection gene, will enable the MLO gene to be mutagenized and therefore unavailable to the powdery mildew fungus to establish infection, making the dogwood resistant to this fungus. This can allow the progression of disease resistance development in flowering dogwood trees against fungus across the board.