Stanley J RouxProfessor
Distinguished Teaching Professorsroux@austin.utexas.edu
The University of Texas at Austin
Molecular Biosciences, College of Natural Sciences
Austin, TX 78712
We are studying how the stimuli of light and gravity alter patterns of plant development. In our studies of light-induced responses we have found that ectoapyrase, an enzyme whose expression is strongly regulated by the photoreceptor phytochrome, can modulate the levels of extracellular ATP [eATP], and that, surprisingly, changes in [eATP] can influence hormone transport, the growth of plant cells and organs (including pollen tubes, root hairs, hypocotyls, roots and leaves), wound responses, and toxin resistance in Arabidopsis and other plants. This indicates that eATP, which is a physiological regulator in animals, also influences plant growth and development, and we are investigating how this happens. For our gravitational studies we are using two model systems, Arabidopsis and spores of the fern Ceratopteris richardii. In Arabidopsis we are using genetic approaches to evaluate the role of annexins, which mediate the secretion of wall materials to growing points of cells, in gravitropic growth. In Ceratopteris spores, where gravity directs polarity development, we are using microarrays to compare the pattern of gene expression in space-flown vs. earth-grown cells, so as to identify genes needed for early stages of the spore’s graviresponse, and we using a Micro-Electro-Mechanical system (MEMS) to document very rapid changes in the transport activity of calcium channels and pumps that are directed by gravity. We are also studying the role of extracellular nucleotides in regulating polarized calcium transport changes and other early signaling steps that direct the gravity response in single spore cells.
2016. Tripathy M, Clark G, Roux SJ. 2016. Apyrase inhibitors enhance the ability of diverse fungicides to inhibit the growth of different plant pathogenic fungi. Molecular Plant Pathology. DOI : 10.1111/mpp.12458.
2016. Clark G, Russell J, Enyeart P, Gracia B, Wessel A, Jarmoskaite I, Polioudakis D, Stuart Y, Gonzalez T, MacKrell A, Rodenbusch S, Stovall GM, Beckham JT, Montgomery M, Tasneem T, Jones J, Simmons S, Roux S. 2016. Science Educational Outreach Programs That Benefit Students and Scientists. PLOS Biology. DOI:10.1371/journal.pbio.1002368.
2015. Vanegas DC, Clark G, Cannon AE, Roux S, Chaturvedi P, McLamore ES. 2015. A self-referencing biosensor for real-time monitoring of physiological ATP transport in plant systems. Biosens Bioelectron. 74: 37-44.
2015. Cannon AE, Salmi ML, Bushart TJ, Roux SJ. 2015. Studying molecular changes during gravity perception and response in a single cell. Methods Mol Biol. 1309:199-207.
2015. Chiu T-Y, Lao J, Manalansan B, Loqué, Roux SJ, Heazlewood JL. 2015. Biochemical characterization of Arabidopsis APYRASE family reveals their roles in regulating endomembrane NDP/NMP homeostasis. Biochem J. 472: 43-54.
2015. Wang X, Ma X, Wang H, Li B, Clark G, Guo Y, Roux S, Sun D, Tang W. 2015. Proteomic study of microsomal proteins reveals a key role for Arabidopsis Annexin 1 in mediating heat stress-induced increase in intracellular calcium levels. Molecular & Cellular Proteomics 14: 686-694.
2015. Yang X, Wang B, Farris B, Clark G, Roux SJ. 2015. Modulation of root skewing in Arabidopsis by apyrases and extracellular ATP. Plant & Cell Physiol. 56: 2197-2206.
2014 Lim MH, Wu J, Yao JC, Gallardo IF, Dugger JW, Webb LJ, Huang J, Salmi ML, Song J, Clark G, Roux SJ, Apyrase suppression raises extracellular ATP levels and induces gene expression and cell wall changes characteristic of stress responses. Plant Physiol 164: 2054-2067
2013 Bushart TJ, Cannon AE, Ul Haque A, San Miguel P, Mostajeran K, Clark GB, Porterfield DM, Roux SJ, RNA-seq analysis identified potential modulators of gravity response in spores of Ceratopteris (Parkeriaceae): Evidence for modulation by calcium pumps and apyrase activity, Am J Bot 100: 161-174
2012 Liu X, Wu J, Clark G, Lundy S, Lim M, Arnold D, Chan J, Tang W, Muday GK, Gardner G, Roux SJ, Role for apyrases in polar auxin transport in Arabidopsis, Plant Physiol 160: 1985-95
2011 Salmi M, ul Haque A, Bushart TJ, Stout SC, Roux SJ, Porterfield DM, Changes in gravity rapidly alter the magnitude and direction of a cellular calcium current, Planta 233: 911-920
2011 Clark G, Fraley D, Steinebrunner I, Cervantes A, Onyirimba J, Liu A, Torres T, Tang W, Kim J, Roux SJ, Extracellular nucleotides and apyrases regulate stomatal aperture in Arabidopsis1, Plant Physiology 156: 1740-53 view
2010 Clark G, Torres J, Finlayson S., Guan X, Handley C, Lee J, Kays J, Chen ZJ, Roux SJ, Apyrase (NTPDase) and extracellular nucleotides regulate cotton fiber elongation in cultured ovules, Plant Physiology 152: 1073-83