Testing ideas in model plants, and then moving them to crops
By equipping farmers with higher-yielding crops, we can ensure that everyone has enough food to lead a healthy, productive life.
The RIPE project, funded by the Bill and Melinda Gates Foundation, is exploring seven opportunities or objectives to improve photosynthesis. Each photosynthetic modification is tested in a single genotype of a model crop, tobacco. Tobacco was chosen as the initial test crop because it is relatively easy to engineer and work within the laboratory, greenhouse, and field, allowing us to apply the engineering principles of design, test, build until we achieve success. Photosynthesis is highly conserved across plants, meaning any breakthroughs identified in tobacco should be transferrable to important food crops.
Once the team identifies an opportunity to improve photosynthesis and boost crop productivity, we begin the process of translating these successes into staple food crops such as cassava, maize, soybean, rice, or cowpea.
Relaxing photoprotection and Photorespiratory bypass
At CSIRO we are focussing on translating the more promising results from two of the RIPE objectives - relaxing photoprotection and photorespiratory bypass - into cowpea for field evaluation. Based on the promising results found in tobacco, where biomass could be increased by accelerating recovery from non-photochemical quenching or by bypassing photorespiration, we will transform cowpea to copy those approaches.
We will produce a large number of independent transgenic cowpea lines and select amongst them for lines with optimal expression of the targeted genes. We expect an increase in grain yield in this important food legume. We started testing the Relaxing photoprotection approach and more recently we have also stared the work with the Photorespiratory bypass.
Relaxing photoprotection tests
We have conducted two filed trials in Puerto Rico to test the field performance of 30 independent, single-insertion transgenic cowpea lines with Relaxed photoprotection. The results so far indicate that the transgenic lines do not perform any better than the control. We discovered that in the transgenic lines the levels of the leaf pigment zeaxanthin were reduced too much, which could affect plant performance. We are planning to generate a second iteration of transgenics by fine tuning the expressing if the targeted genes: zeaxanthin, antheraxanthin and violaxanthin.