A Network of European Researchers, termed 'Plasmonet', has been established to combine expertise on chloroplast biology and transformation technology to study the practical procedures for, and biochemical/physiological consequences of, genetic transformation of the plastid genome (plastome) of crop plants, and to demonstrate the efficacy of a commercially important trait introduced into the plastome.
The impetus behind this initiative comes from increasing recognition that the plastome is a particularly attractive target for the introduction of genes carrying agronomically valuable traits into crop plants, and that plastid transformation provides a valuable new tool for evaluating the contribution of plastome genes to the essential, lifegiving, process of photosynthesis. These two points are interlinked, as any modification of the plastome for biotechnological goals, has implications for the proper functioning of the plastome, and the interplay between it and the nucleus. Plasmonet has identified several key elements of the development of plastid transformation technology, and parallel investigations on the function and regulation of plastid genes, and these provide the essence of the current proposal. They are concisely stated in the following list of objectives:
1. Efficient plastid transformation procedures will be established for three important European crops, potato, tomato and oilseed rape.
2. Environmentally friendly, and versatile, vectors will be developed for efficient plastid transformation. Critical elements of this will include: - a system for the subsequent elimination of heterologous, antibiotic resistance, marker genes from the plastome.
- assessment of efficiency of co-transformation of unlinked markers, to allow the routine use of structural antibiotic insensitivity for selection.
- vectors originally developed for Solanaceous species will be adapted for Brassica crops, through the substitution of appropriate homologous flanking sequences.
3. To ensure efficient and appropriate expression of transgenes in the plastome, control of plastid genes will be examined, including: - the relative roles of promoters recognised by
nuclear- and plastid-encoded RNA polymerases.
- the role of transcription factors.
4. Targeted gene inactivation will be used to investigate the biological roles of genes encoding components of the plastidic NADH dehydrogenase complex (ndh genes).
5. Plastid transformation will be used to examine critical interactions between nuclear and plastid genomes,
6. A commercially important trait, cytoplasmic male sterility, will be introduced into tomato and oilseed rape through plastid transformation.
Funding SchemeCSC - Cost-sharing contracts
6080 AA Haelen
CB2 3EA Cambridge