Amy Mackenzie

Position: PhD Student
Place of birth: England
Language: English
Scholarship: Research Training Program (RTP), and CSIRO PhD Top-Up Scholarship
Advisors: Dr Sambasivam Periyannan, A/Prof Lee Hickey

Amy-action shot in glasshouse

 

Research topic 

Rust diseases of wheat pose the largest biotic threat to global wheat production. The preferred method of rust disease control is through the deployment of wheat cultivars carrying genetic resistance because it is more effective, economical, and environmentally friendly than fungicide use. Researchers must identify novel genes that confer resistance to rust diseases in an effort to increase our repertoire of durable and effective genetic resistance for use in the field.

Wheat rust resistance genes generally fall into one of two categories; all-stage resistance which manifests at the seedling stage, and adult-plant resistance which manifests during adulthood. Generally speaking, all-stage resistance is strong and specific to certain races of a single rust pathogen, while adult-plant resistance is weak but broad-spectrum, often providing resistance to all races of multiple pathogens. A combination of both types of resistance is most desirable in the field.

Using a combination of resistance gene identification techniques, I aim to identify a gene responsible for adult-plant resistance to leaf rust and a gene responsible for all-stage resistance to stripe rust. My research utilises recent advancements in wheat genomic research, including the annotated hexaploid and tetraploid wheat genome assemblies and the recently developed wheat Pan Genome, coupled with RNA sequencing and expression analysis, and more traditional mapping techniques for gene discovery. During my PhD project, I will also examine the additive effects of five different adult plant resistance genes to leaf rust, which often provide partial resistance that is insufficient on their own.

 

 

Objectives 
Identification and validation of candidate genes for the leaf rust adult plant resistance gene, Lr49
Create a physical map of the Lr49 locus based upon a high-resolution map
Use RNA sequencing and expression analysis to identify likely candidates for Lr49
Validate Lr49 candidates using a high-resolution mapping population and a mutant population of loss-of-resistance lines
Confirm Lr49 candidates through complementation tests
Identification and validation of candidate genes for the stripe rust all-stage resistance gene, Yr63
Use the mutagenesis, resistance gene enrichment and sequencing (MutRenSeq) based strategy to identify candidate genes for Yr63
Screen Yr63 candidates using a mapping population
Confirm Yr63 candidates through complementation tests
Examination of the additive effects of adult-plant resistance genes to leaf rust
Develop and genotype adult-plant resistance gene crosses
Score F3 progeny containing different combinations of leaf rust adult-plant resistance genes for resistance to leaf rust