Trans C4 · Deciphering Regulatory DNA and Transcription Factor Binding Sites in C3 and C4 Species with Varying Water Use Efficiencies

Deciphering Regulatory DNA and Transcription Factor Binding Sites in C3 and C4 Species with Varying Water Use Efficiencies

Water-related stress is the number one limiting factor for plant productivity and also human well-being. Unfortunately, one-third of the current world population faces water shortages and by 2025, two-thirds are expected to experience water stress conditions, and 1.8 billion people will be subjected to absolute water scarcity. Unless ameliorating measures are taken, almost half the world's population will be highly water-stressed by 2030. Moreover, the UN World Water Development Report 2015 estimates that global water demand will increase by 55%, with agriculture the greatest user. To make matters worse by 2050 agricultural production has to increase by 60% to provide feed and fuel. At least one in nine worldwide do not have enough food to eat, hence improving crop plants to be both productive and water-efficient users is a matter of life. The C4 photosynthetic pathway not only boosts plant productivity by ~50% but also increases water use efficiency. C4 photosynthesis is a remarkable trait that is thought to have evolved in response to environmental factors including increased aridity and seasonality. In contrast to C3 crops where CO2 fixation is catalysed by RuBisCO in mesophyll cells of leaves, most C4 plants use two distinct and specialized cell types for photosynthesis. All C4 plants concentrate CO2 in leaves, increasing productivity by ~50%, but also maintaining lower stomatal conductance than C3 species. For example, under heat stress induced by a temperature rise from 20°C to 30°C, C3 plants double water loss via transpiration whilst C4 plants are able to decrease the diffusive efflux of water vapour by 50%, and are therefore considered as water-efficient users. In summary, C4 photosynthesis allows increased water use efficiency but also underpins significant improvements in crop yield. A full understanding of this remarkable phenomenon would facilitate water efficient and productive crops to be engineered in the future. The experimental programme is designed to provide significant new insight into the mechanisms underpinning differences in gene expression associated with contrasting photosynthetic and water use efficiencies.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз