Continuing our series on Great British bioscience pioneers, we profile Dr Danny Thorogood, a plant breeder and geneticist at the Institute of Biological, Environmental and Rural Sciences at Aberystwyth University. His work on the genetics of plants has many applications, including in helping to improve the diversity and resilience of some of the world's most important crops.
How did your bioscience career first begin?
I was awarded an Agricultural and Food Research Council PhD Studentship to study the genetics that prevent grasses from self-fertilising at the Welsh Plant Breeding Station (WPBS) under the supervision of Professor Mike Hayward in 1984. The genetics of this self-incompatibility system were first elucidated in 1956 and I was fortunate to meet one of the joint discoverers, David Hayman, from the University of Adelaide, very early on in my plant science career. I also benefitted from close collaborations between the WPBS and Birmingham University, and in particular, the expertise and knowledge of Michael Lawrence, the son of the famous practical plant breeder, WJC Lawrence, from the John Innes Centre. Careers are often fired by inspirational teachers and I had two of them at school. And I always admired, and still admire, the work and clear logical thinking of Jack Heslop-Harrison who had laboratory space at Plas Gogerddan, the home of the Welsh Plant Breeding Station, where I have remained throughout my career.
What are you working on now?
Although a plant breeder is, by nature, a generalist, I am still, among other things, actively researching the self-incompatibility (SI) system in grasses using the perennial grass, Lolium perenne, as my model species. I am fortunate in having access to a superb genomics platform and supporting expertise in next generation sequencing technology funded by BBSRC. Although the exact nature of the genes involved in grass SI has not been elucidated, we have been able to pick out a small handful of candidate genes for both SI loci known to be involved. This has been done using a map-based approach which has been considerably enhanced by technological developments that have made genome and transcriptome sequencing and assembly accessible to studies of so-called minor plant species. L. perenne is a good model grass for compatibility studies, and, of course, we now know that its genetic and genomic organisation is very similar to other grass species including the major cereal crops. So, findings in our model SI species are relevant to the understanding and manipulation of self- and cross-incompatibility for increasing the diversity of our germplasm pools in major staple crop breeding programmes.
What advances have you seen in your chosen field in the last 20 years?
Research has been, at times, frustrating. Major advances have been made in the understanding of the molecular genetics of numerous SI systems under the control of single genes. Researchers now know the gene complexes involved in several plant families, yet more complex systems are still poorly understood. In fact, the more we study L. perenne populations, the more we realise its system is more complex than originally proposed. As well as SI mechanisms to prevent self-fertilisation, plants will mostly not hybridise with close species relatives. The physiological rejection process is often indistinguishable from the process of self-recognition and rejection. We have found evidence of cross-incompatibility in L. perenne populations and have identified two genomic regions unlinked to the two SI loci that might be involved in this process. What's more, cross-incompatibility occurs only with certain combinations of SI and cross-incompatibility genes.
What are the five key bioscience milestones that you've been part of?
- 1992 Self-compatibility was transferred from the self-fertile species, Lolium temulentum, into normally self-incompatible L. perenne and L. multiflorum
- 1992 Temporary self-compatibility was induced by high temperature treatment of whole plants to facilitate the production of inbred lines
- 2002 The S and Z incompatibility loci were located on chromosomes 1 and 2 of a genetic map of L. perenne. A further locus on chromosome 3 was shown to interact with the S-locus to cause cross-incompatibility of certain gene combinations
- 2005 Self-fertile plants were found to carry self-fertility genes at the S-locus and a further locus on chromosome 5
- 2014 The self-incompatibility of plants of a population of L. perenne plants was found to be associated, as expected, with the S and Z loci. But two other loci were found to affect unilateral cross-incompatibility where a cross was incompatible using one of the plants as the female and one as the male, yet in the other direction the cross was fully compatible
How has BBSRC supported you throughout your career?
Although I have been funded by industry through much of my career as a plant breeder, my work has been supported by the infrastructure and basic science outputs of the BBSRC funded Institute of Biological, Environmental and Rural Sciences (IBERS) at Aberystwyth University. My work on the genetics of self-incompatibility is currently funded by an Institute Strategic Programme Grant and I also received a Follow on Fund grant to investigate using gene-specific DNA markers to assist targeted manipulation of flowering time and duration and seed yield potential in grass crops. The findings of this work are currently being applied in the Institute's perennial ryegrass breeding programme.