Periodic Reporting for period 4 - FutureAgriculture (Transforming the future of agriculture through synthetic photorespiration)
Reporting period: 2019-07-01 to 2021-03-31
FutureAgriculture aims to boost agricultural productivity by designing and engineering plants that directly overcome the deficits of natural photorespiration and that support higher photosynthetic rate and yield. Alternative metabolic pathways that can bypass photorespiration without releasing CO2 are screened in silico by taking into account all known enzymes, as well as enzymes that could be easily evolved from them. The synthetic enzymes are integrated with existing ones to obtain entirely new pathways optimized by chemical logic, which will, in turn, be realized in vitro and then in vivo within bacteria and plants. Their implementation in plants is expected to significantly increase plant growth rate and biomass yield under various environmental conditions. This will provide the basis for increasing agricultural productivity of the crops that comprise >60% of agricultural production, including rice, wheat, barley, oat, soybean, cotton, and potato.
The TaCo pathway has already been partially realized in cyanobacteria (photosynthetic bacteria living in the soil and water) and also been implemented in model plants, some of them showing a significant physiological advantage compared to wild-type plants when grown under extreme drought conditions, which enhances photorespiration. The FUTUREAGRICULTURE team is now validating the results in plants and planning to transfer them to major crops.
These promising results provide hope that the new pathways developed in FUTUREAGRICULTURE perform similarly well under difficult or challenging conditions in the field because they are much more CO2 efficient. It is expected that plants with the new pathways are more tolerant to the lack of water and produce more biomass per unit of land and of time than at present.
Along these lines, FutureAgriculture offers not an incremental improvement but rather a leap in agricultural productivity. Most other research efforts that aim to improve photosynthetic yield involve enormous implementation barriers. In contrast, FutureAgriculture’s engineering aims can be achieved within a reasonable timeframe as they are strictly genetic/metabolic and do not involve morphological or any other structural modifications. Hence, the development and implementation of synthetic photorespiration routes can transform the future of agriculture.
Furthermore, while the improvement of photosynthetic rate and yield via transgenic approaches has been a hot research topic for many years, these efforts focused on introducing existing pathways into new plant hosts. FutureAgriculture adopts a radically different approach. Rather than reshuffling and grafting existing enzymes in a fashion that resembles natural evolution and is in line with current metabolic-engineering thinking, the project systematically explores novel pathways that cannot be obtained by mixing and matching of existing, natural enzymes. FutureAgriculture’s approach demands the de novo engineering of new enzymes to catalyze metabolic transformations that are unknown in nature. These synthetic enzymes are integrated with existing ones to obtain entirely new pathways optimized by chemical logic, which will in turn be realized within bacteria and plants. Given the combinatorial nature of metabolic pathways, the addition of only one novel reaction dramatically expands the solution space of possible pathways, thus fully realizing the potential of synthetic biology. Yet, so far, only a handful of studies implemented synthetic pathways that harbor novel enzymes. FutureAgriculture takes this strategy to a new level by constructing de novo pathways within the very core of carbon metabolism.