Plant productivity is determined in large part by the partitioning of reduced carbon (sugar) between the sites of production (photosynthetic tissues) and the sites of utilization (growing tissues such as roots and young leaves, etc). To judiciously engineer increased yield of crop plants, a better understanding of the regulation and efficiency of sugar transport throughout the plant is required. Work by the principal investigators and others has shown that the up-regulation of proton-pyrophosphatases (H+-PPases) results in enhanced root and shoot growth and increased photosynthetic output. The principal investigators hypothesize that plant H+-PPases play a crucial role in regulating sucrose synthesis, partitioning and utilization. The hypotheses will be tested using a combination of genetic, metabolomic, molecular biological, and ultra-structural approaches. The research will shed light not only on the fundamental physiological subject of carbon utilization and transport, but also has potential downstream applications since increased H+-PPase activity enhances plant biomass, nutrient uptake capacities, and stress tolerance. With growing populations, decreasing arable land, and a national desire to exploit plants for biofuels, understanding the role of H+-PPases in plant growth could be transformative.
The outcomes of this project will be made available to the scientific community through timely publication and by the participation of the principal investigators in their undergraduate and graduate education programs. The professional development of undergraduate and graduate students, and postdoctoral fellows will occur at the interface of genetics, physiology, cell biology and cutting-edge metabolomics. The project participants will work together with the Arizona State University "Ask a Biologist" program to develop topical content on biomass for fuel and how it relates to the movement of energy throughout biological systems.