Engineering on/off switches for chloroplast protein translation

Project title: Engineering synthetic pentatricopeptide repeat (PPR) proteins as on/off switches for chloroplast protein translation

Application Domain: Foundation Technologies

Close up plant

Marchantia polymorpha. Image: Suvi Honkanen

The challenge

Plant chloroplasts provide a powerful platform for producing high-value biomolecules, such as therapeutic proteins and vaccine antigens. The expression of genes in the chloroplast genome is primarily regulated at the translational level, yet we currently lack effective chloroplast translation control switches.

Our response

We are developing synthetic pentatricopeptide repeat (PPR) proteins that function as targeted on and off switches for chloroplast protein translation using a simple plant, the liverwort Marchantia polymorpha as a model system.


The project will accelerate the use of plant chloroplasts as biofactories. In the longer term, the synthetic PPR proteins developed here are expected to be adaptable to a wide range of genetic systems to control gene expression in many biotechnological applications.


Suvi Honkanen (Project leader – CSIRO Synthetic Biology Future Science Fellow/ The University of Western Australia), Professor Ian Small (The University of Western Australia), Dr Owain Edwards, Dr Thomas Vanhercke and Dr Surinder Singh (CSIRO)