Natural resistance reservoirs

Lead Supervisor: Dr Neil Hall and Dr Mark McMullan

Location: Earlham Institute; Organisms and Ecosystems

Duration: 6 weeks

Suitable undergraduate degrees: Biology

Project background

Resistance genes are responsible for the recognition of invading pathogens and the initiation of the immune response.  Our understanding of the role of resistance genes in plants has been advanced by their use in crop breeding programs.  However, we still don’t understand their co-evolution (with pathogens) in the wild.  Here we propose to measure the level of genetic diversity and gene flow of a resistance gene among four UK populations of sea beets.  This gene has been identified for its importance for resistance to cercospora in the sugar beet crop.

This project benefits from eleven sea beet reference genomes, and approximately 600 wild sea beet plants recently sequenced at the Earlham Institute.  Using pipelines developed in the Hall group the student will:

• Screen 600 wild genomes for the presence/absence of this resistance gene
• Measure the level of genetic diversity and genetic differentiation at this gene (across four populations, Suffolk to Merseyside)
• Design PCR primers for this gene and then test those primers directly on samples of wild hosts (fieldwork)

The underlaying population genetic and evolutionary theory tells us that, for resistance genes to remain effective against a diverse array of pathogens, they should both retain higher levels of polymorphism, and  be shared between populations more readily than other genes (balancing selection).  The student will use bioinformatic data to test these expectations and then test their PCR assay in the field to see if they can directly screen wild hosts for the presence/absence of this gene and associated pathogens.

The project works in ecology, biodiversity and systematics and has a specific focus on population genetics, gene flow, population structure, genetic drift, and adaptation.