Project Description

Project full title:   Mechanisms of transgene integration and expression in crop plant plastids: underpinning a technology for improving human health

Project acronym:   PLASTOMICS

Research topic addressed:   Multidisciplinary functional genomics approaches to basic biological processes

Project abstract:

The aim of the project is to define the mechanisms of several key stages of plastid transformation and foreign gene expression in different plastid types in tobacco, tomato and potato. Plastid transformation is the most precise method of integrating foreign genes in plants. It offers a cheap large-scale production platform for therapeutic proteins, such as hormones and vaccines, and also for food of improved nutritional quality. Although plastid transformation and high level expression of foreign proteins in chloroplasts in tobacco leaves is well established, the commercial success of plastid transformation as a production platform will depend to a large extent on high level expression in non-green plastids, such as chromoplasts and amyloplasts, in crops that are amenable to processing.

• transgene integration and marker gene excision via homologous recombination
• regulated gene expression in chloroplasts, chromoplasts and amyloplasts
• protein degradation in different plastid types

The expression of identified genes will be altered in transgenic plants by RNAi and constitutive overexpression and the consequences for plastid transformation and foreign gene expression established. These experiments will be combined with biochemical studies on the plastid transcriptional apparatus and promoter characterisation to define regulatory elements for optimised expression in chromoplasts and amyloplasts. The complete nucleotide sequences of the plastid genomes (~ 150 kbp) of tomato and potato will be determined, to facilitate future plastid transformation strategies. Factors affecting the stability of human serum albumin, somatotropin and rotavirus VP6 protein in plastids will be examined to optimise the production of these proteins.