P0859 Defining the maize Pyruvate orthophosphate dikinase regulatory network

Pinghua Li , Institute of Tropical Biosciences & Biotechnology , Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
Rita Giuliani , School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164, USA.
Wagner L. Araujo , Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany.
Lauren Dedow , Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA.
Yaqing Si , Department of Statistics, Iowa State University, Ames, Iowa 50011, USA.
Cankui Zhang , Department of Plant Biology, Cornell University, Ithaca, New York 14853, USA.
Thomas Slewinski , Department of Plant Biology, Cornell University, Ithaca, New York 14853, USA.
Peng Liu , Department of Statistics, Iowa State University, Ames, Iowa 50011, USA.
Qi Sun , Computational Biology Service Unit, Cornell University, Ithaca, New York 14853, USA.
Gerald E. Edwards , School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164, USA.
Alisdair R. Fernie , Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany.
Robert Turgeon , Department of Plant Biology, Cornell University, Ithaca, New York 14853, USA.
Alice Barkan , Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA.
Asaph B. Cousins , School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164, USA.
Thomas P. Brutnell , Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA.
C4 plants, like maize, display a higher photosynthetic efficiency, lower CO2 compensation point and reduced photorespiration relative to C3 plants under hot, dry conditions. These benefits provide C4 crops with a distinct growth advantage, better water use efficiency and higher rates of biomass accumulation. An important aim of our current research is gain a deeper understanding of the mechanisms that regulate C4 photosynthesis.  One application of this work would be to engineer C3 crops with C4 traits thus improving yield.

Pyruvate orthophosphate dikinase (PPDK) is a key and rate-limiting enzyme in maize C4 photosynthesis, which catalyzes the regeneration of the substrate phosphoenolpyruvate (PEP) for assimilation of CO2 by PEP carboxylase. Although the biochemical function of PPDK is well understood, little is known of the transcriptional network regulating PPDK. In this study, we characterized several transposon insertions in the maize PPDK gene.  Through detailed histological, physiological and molecular analyses (RNA-seq, GC-MS) we explore the PPDK regulatory network and examine the physiological consequences of a loss of PPDK function.