The Hypothesis

The yield of rice, a ‘C3-type’ grass, is limited by the inherent inefficiency of C3 photosynthesis. On multiple independent occasions evolution surmounted this inefficiency through the establishment of the C4 photosynthetic pathway. C4 species such as maize and sorghum are more efficient at carbon assimilation than C3 species, and in addition they display greater water use efficiency, better nitrogen use efficiency and higher-temperature tolerance. The underlying hypothesis of this research is that photosynthetic efficiency in rice can be improved by engineering the photosynthetic machinery to include functional components of the C4-type pathway, and that increased photosynthetic efficiency will result in higher yield plus greater resilience to abiotic stresses associated with climate change.