The host: Resistance gene isolation and realising the potential

Kim Hammond-Kosack, Rothamsted Research

Most plants are resistant to most pathogens. This is because plants have evolved sophisticated systems for the recognition of non-self that in turn leads to the activation of both local and systemic plant defence responses. Over the past twelve years many novel genes, proteins and molecules have been discovered as a result of investigating both compatible and incompatible plant-pathogen interactions. We now recognise that both interaction outcomes involve dramatic cellular reprogramming events in plant tissues and that some parallels exist between plant defence and the animal innate immune response.

This presentation will focus on the different classes of resistance genes, how they were isolated, how they are thought to function in pathogen perception and defence activation and how novel functionalities may be evolving at resistance gene loci. Many fundamental questions remain stubbornly unanswered. Where research breakthroughs are urgently required these will be pin-pointed and the value of post-genomics approaches reviewed.

Most of the knowledge gained on resistance genes / proteins and the defence responses activated arose from investigations on model plant-pathogen interactions. Unfortunately most attempts to harness this new knowledge to engineer improved disease resistance in crops have so far failed even though good gene efficacy has been shown. Currently underway is a shift in emphasis towards strategies to enhance marker-assisted breeding and the use of vectors containing highly regulated transgenes that confer resistance in several distinct ways.

Acknowledgements

Rothamsted Research receives grant aided support from the Biotechnology and Biological Sciences Research Council.

Selected references

1. Hammond-Kosack KE and Jones JDG (2000) Responses to Plant Pathogens In " Biochemistry and Molecular Biology of Plants" p 1102 - 1156 Ed BB Buchanan, W Gruissem and RL Jones. Pp1367 American Society of Plant Physiology, Rockville, Maryland, USA
2. Dangl JL and Jones JDG (2001) Plant pathogens and integrated defence responses to infection Nature 411, 826-833.
3. Hammond-Kosack KE and Parker JE (2003) Deciphering plant-pathogen communication: Fresh perspectives for molecular resistance breeding. Current Opinions in Biotechnology 14, 177-193.
4. Martin GB, Bogdanove AL and Sessa G (2003) Understanding the functions of plant disease resistance proteins. Annual Review Plant Biology 54, 23-61.
5. McDowell JM and Simon SA (2006) Recent insights into R gene evolution. Molecular Plant Pathology 7, 437-488.
6. Dangl JL and Jones JDG (2006) The plant immunity system. Nature Dec issue.