Daniel R Bush
Professor and Vice Provost for Faculty AffairsOffice: 108 AdministrationPhone: 970-491-0212Education: Ph.D., UC BerkeleyEmail: firstname.lastname@example.org
Although plants are photoautotrophic organisms, they are composed of many heterotrophic tissue systems, such as roots, flowers, seeds, and developing leaves, that depend on carbon and nitrogen import for growth and development. In general, sucrose and amino acids are transported to the heterotrophic cells from mature leaves. This process is known as assimilate partitioning and it is a fundamental activity that allows plants to function as multicellular organisms.
My laboratory provided the first biochemical and molecular descriptions of several plant sugar and amino acid transport systems that are key contributors to resource allocation within cells and between organs. We initially described these transporters using an in vitro biochemical assay that allowed us to define the transport properties and bioenergetics of these important carriers. To identify the genes encoding the plant's sugar and amino transporters, we used functional complementation of yeast transport mutants with plant cDNA expression libraries (PNAS 90:7441-7445). The yeast system is very useful because it allows us measure key transport properties and protein structure/function relationships when plant transport proteins expressed in yeast cells (PNAS 95:9025-9030).
The unifying theme of our research today is understanding how plants regulate resource allocation between "source and sink" tissues. To tackle this complex question, we are using genetic and biochemical strategies to identify the signal transduction pathways that regulate assimilate partitioning. We discovered a unique sucrose-mediated signal transduction pathway that regulates the expression and protein abundance of the sucrose transporter that is responsible for phloem loading (PNAS 95:4784-4788; PNAS 99:10876-10880). We also discovered that multiple nitrogen-metabolites regulate amino acid transporter gene expression, and have now focused on understanding nitrate as a signal molecule that regulates unique patterns of plant gene expression. That research led to the discovery of a novel protein that appears to regulate cell wall structure (Plant Phys 152: 904-917, 2010). In a complementary biofuels research project, we are using genetic and genomic tools in rice as a model plant to identify genes that control primary productivity (biomass per m2). In addition to advancing the understanding of fundamental processes in plant growth and development, our research will allow us to develop rational strategies to improve crop productivity for both food and fuel.
Hermans C, Porco S, Vandenbussche F, Sascha G, De Pessemier J, Van Der Straeten D, Verbruggen N, and Bush DR 2011. Dissecting the role of CTL1 in nitrate-dependent changes in root architecture. Plant Physiology 157:1313-1326
Ainsworth EA and Bush DR 2011. Carbohydrate export from the leaf - A highly regulated process and target to enhance photosynthesis and productivity. Plant Physiology 155: 157-168
Jahn CE, JK McKay, R Mauleon, J Stephens, KL McNally, DR Bush, H Leung, and JE Leach 2011. Genetic variation in biomass traits among 20 diverse rice varieties. Plant Physiology 155: 64-69
Hermans C, Porco S, Verbruggen N and Bush DR 2010. Chitinase-like protein CTL1 plays a role in altering root system architecture in response to multiple environmental conditions. Plant Physiology 152: 904-917
Weyer KM, Bush DR, Darzins AL, and Willson BD 2010. Theoretical maximum algal oil production. BioEnergy Research 3:204-213
Bush DR 2009. Overlook agricultural research at our peril. Proc. Natl. Acad. Sci. USA 106: E108
Dundar E & Bush DR 2009. BAT1, a Bidirectional Amino Acid Transporter in Arabidopsis. Planta 229:1047-1056
Bush DR and Leach J 2007. Translational Genomics for Bioenergy Production: There’s room for more than one model. Plant Cell 19: 2971-2973
Liu X and Bush DR 2006. Expression and transcriptional regulation of amino acid transporters in plants. Amino Acids 30:113-120
Ransom-Hodgkins W, MW Vaughn, and DR Bush 2003. Protein phosphorylation mediates a key step in sucrose-regulation of the expression and transport activity of a beet proton-sucrose symporter. Planta 217:483-489
Vaughn MW, GN. Harrington, and DR Bush 2002. Sucrose-mediated transcriptional regulation of sucrose symporter activity in the phloem. Proc. Natl. Acad. Sci. USA 99:10876-10880
Coruzzi G and Bush DR 2001. Nitrogen and carbon nutrient and metabolite signaling in plants. Plant Physiol 125: 65-68
Bush DR 1999. Sugar transporters in plant biology. Current Opinion in Plant Biol. 2:187-191
Chiou TJ and DR Bush 1998. Sucrose is a signal molecule in assimilate partitioning. Proc. Natl. Acad. Sci. USA 95:4784-4788
Chang H-C and DR Bush 1997. Topology of NAT2: a prototypical example of a new family of amino acid transporters. J. Biol. Chem. 272: 30552-30557
Hsu L-C, TJ Chiou, L Chen, and DR Bush 1993. Cloning a plant amino acid transporter by functional complementation of a yeast amino acid transport mutant. Proc. Natl. Acad. Sci. USA 90:7441-7445
Bush DR 1993. Proton-coupled sugar and amino acid transporters in plants. Annu Rev Plant Physiol and Plant Mol Biol 44:513-542