Karen Massel

Honours/MSc - Expanding the sorghum genotypes used for CRISPR/Cas9 gene editing

As the climate becomes more unpredictable, global agricultural production will continue to face challenges to meet the rising food demands. Creative approaches should be integrated into breeding programs utilising all available tools to overcome the pressure these shifting climate realities place on food security. CRISPR/Cas9 is a revolutionary genome editing system that can create targeted genetic alterations such as gene knockouts, nucleotide modifications, large insertions/deletions, as well as regulation of genetic networks. However, there is a major limitation in the implementation of this techniques based on their recalcitrant nature in tissue culture.

In sorghum, there is a model transformable genotype that is often used in biotechnolgical studies. However, if we could find alternative genotypes improtant to breeding programs, we can improve the speed of implementing gene edited outcomes within the breeding pipeline, as well as expand the types of traits we are capable of studying. This would enhance the feasibility of implementing these novel genetic outcomes in breeding programs and allow for researchers to really showcase the potential of this technology in crops. There a few different methodologies that can be used to test these lines in tissue culture with help from breeding programs.

Honours/MSc - Gene editing to manipulate inflorescence development and boost yield

Grain sorghum is the fifth most important cereal crop worldwide and is a staple food for over half a billion people worldwide. Although it has many inherent drought and heat tolerance traits which make it an important crop for global food security efforts, its widespread use as a food/feed crop are curbed by its low yields and grain quality. This project is utilising new breeding technologies such as CRISPR/Cas9 gene editing to improve our understanding of floret and panicle architecture in an attempts to boost yields. Previous research into studying genes involved in stem cell development and maintenance have shown that through targeted modifications, reserachers can have significant boosts to yield through tweaking the expression by targeting the promtoer region of major target genes. We currently have mutant knockout lines that show a promising fasciated phenotype, and we believe through targeting the promoter of these genes we can reduce the deleterious effects of a complete knockout and create mutant sorghum varieties wtih improved yield.

Honours/MSc - Gene editing seed storage proteins for improved grain quality

Sorghum bicolor is an important animal feedstock cereal crop throughout Australia and the southern United States, where its use as a food product is limited by issues with low calorific and nutritive value. Qualities such as low digestibility and essential amino acid content are directly attributed to the kafirin grain storage proteins. Specifically, the β- and γ-kafirins are low in protease cleavage sites and high in cysteine residues, forming a highly cross-linked shell that encapsulates the more digestible α- and δ-kafirins in the core of the protein bodies. We have developed gene edited lines with significantly improvements in grain protein digestibility using in vitro assays for both monogastric and ruminants. Further work is required to demonstrate changes in starch properties and visualise microstructural modifications within the protein-starch matrix via microscopy.

Honours/MSc - Gene editing of elite grass species

Developing tissue culture and gene editing systems for elite grass species will provide the framework to perform a variety of experiments for a range of industries, and can have a huge impact for sustainable living. Providing a mechanism for quick genetic gains could provide councils with climate-adapted grass that use less water or fertiliser, or producing non-allergenic varieties that reduce the levels of hayfever that is often triggered through exposure of grass pollens. Alternatively, developing a system could help produce better forage feed for pasture grasses that would provide a superior feed for a range of animals for more sustainable animal production.