Dr Liz Dennis ‘Hybrid vigour in plants; how does it work?’

Liz Dennis is an eminent plant molecular biologist and a CSIRO Fellow in the Division of Agriculture, CSIRO in Canberra. She is also a Distinguished Professor at University of Technology, Sydney. She leads a team of research workers studying the molecular basis of hybrid vigour. She holds a BSc (Hons I) and a PhD from the University of Sydney, Australia, and is author or editor of more than 300 distinguished publications.

Liz was elected to the Australian Academy of Technological Sciences and Engineering in1987 and to the Australian Academy of Science in 1995.

Her research has led to significant advances in our understanding of the molecular basis of plant development, especially flowering and seed development, plant gene regulation including epigenetic regulation, and plant responses to environmental stress such as water logging conditions. Most recently she has been involved in investigating the molecular basis of heterosis (hybrid vigour) and epigenetics (changes in the appearance or gene function of an organism not due to actual changes in its DNA

sequence). Her contributions to our understanding of gene expression, the molecular bases of plant development, plant gene regulation, and mapping plant genomes have been recognized by many invitations to speak at international meetings as well as awards including the Avon Spirit of Achievement Award, the Lemberg Medal of the Australian Society of Biochemistry and Molecular Biology and the inaugural Prime Minister’s Science Prize (jointly with Jim Peacock). She has recently been awarded the Farrer Medal by the Farrer Memorial Trust.

Hybrids have been used in maize cropping for nearly 100 years and more recently in other crops like rice, sorghum and in horticulture. The phenomenon where progeny of a cross perform better that the parents with no added inputs is still not understood. We have used Arabidopsis as a model to study hybrid vigour and come up with some findings that we think also apply to crop plants. We find that normal plant processes are used to generate the large size and increased yield characteristic of hybrids.  A feature of hybrids is that the hybrid advantage only lasts for one generation. We have developed methods to perpetuate the hybrid phenotype in later generations. We aim to understand the molecular features underlying hybrid vigour.