Research objectives and content
Gene silencing is a major limitation to the reliable use of genetically engineered crops. Although extensively described, it is still poorly understood because of the complexity of the chromosomal factors affecting the transgene expression. I have recently developed a straightforward and reproducible system for consistent activation of gene silencing based on transient expression of foreign sequences in transgenic Nicotiana benthamiana plants (transiently induced gene silencing: TIGS). This novel approach takes advantage of the induction of a previously unknown signalling mechanism in plants that mediates sequence-specific systemic gene silencing. I will use transgenic non-silenced Nicotiana benthamiana plants carrying the jellyfish green fluorescent protein (GFP) gene as a model system for TIGS, in order to systematically address the following points:What are the features that make the foreign sequence able to initiate GFP gene silencing ? What is the nature of the signalling molecule ? How is the signal propagated/ maintained in the plant and what type of cells are affected by TIGS ? In addition, TIGS may provide a new tool for analysis of plant gene function and, eventually, for control of plant gene expression. These aspects will also be investigated.
Training content (objective, benefit and expected impact) This project is of major interest to me for the following reasons: -it gives me the opportunity to broaden my knowledge in modern biological techniques and to work on a previously unknown aspect of plant biology that may be of considerable importance in our understanding of plant genetic regulation. -this work will be carried out in a laboratory that is in the forefront of not only the study but also the practical use of gene silencing.- the direct practical outcome of this work is potentially extremely useful (i) for the design of reliable transgenic crops, (ii) for the analysis of plant gene function.
Links with industry / industrial relevance
This project wil probably lead to the development of new strategies for the control of gene expression in plants. The host laboratory has industrial links with ZENECA concerning the development of reversegenetic tools based on gene silencing.