title: Waving and skewing: how gravity and the surface of growth media affect root development in Arabidopsis.
abstract: Arabidopsis seedlings growing on inclined agar surfaces exhibit characteristic root behaviours called 'waving' and 'skewing': the former consists of a series of undulations, whereas the latter is a deviation from the direction of gravity. Even though the precise basis of these growth patterns is not well understood, both gravity and the contact between the medium and the root are considered to be the major players that result in these processes. The influence of these forces on root surface-dependent behaviours can be verified by growing seedlings at different gel pitches: plants growing on vertical plates present roots with slight waving and skewing when compared with seedlings grown on plates held at minor angles of < 90 degrees . However, other factors are thought to modulate root growth on agar; for instance, it has been demonstrated that the presence and concentration of certain compounds in the medium (such as sucrose) and of drugs able to modify the plant cell cytoskeleton also affect skewing and waving. The recent discovery of an active role of ethylene on surface-dependent root behaviour, and the finding of new mutants showing anomalous growth, pave the way for a more detailed description of these phenomena.
authors: Laboratory of Plant Physiology, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland.
authors: Michele
authors: M
authors: Oliva
authors: Laboratory of Plant Physiology, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland.
authors: Christophe
authors: C
authors: Dunand
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D003470:Culture Media; D005030:Ethylenes / Q000378:metabolism; D018522:Gravitropism / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction; D013499:Surface Properties
chemical_list: D029681:Arabidopsis Proteins; D003470:Culture Media; D005030:Ethylenes; C036216:ethylene
references: Abe T, Thitamadee S, Hashimoto T. 2004. Microtubule defects and cell morphogenesis in the lefty1lefty2 tubulin mutant of Arabidopsis thaliana. Plant Cell Physiology 45: 211-220.
references: Baskin TI. 2001. On the alignment of cellulose microfibrils by cortical microtubules: a review and a model. Protoplasma 215: 150-171.
references: Binder BM, O'Malley RC, Wang W, Zutz TC, Bleecker AB. 2006. Ethylene stimulates nutations that are dependent on the ETR1 receptor. Plant Physiology 142: 1690-1700.
references: Blancaflor EB, Masson PH. 2003. Plant gravitropism. Unraveling the ups and downs of a complex process. Plant Physiology 133: 1677-1690.
references: Buer CS, Masle J, Wasteneys GO. 2000. Growth conditions modulate root-wave phenotypes in Arabidopsis. Plant Cell Physiology 41: 1164-1170.
references: Buer CS, Wasteneys GO, Masle J. 2003. Ethylene modulates root-wave responses in Arabidopsis. Plant Physiology 132: 1085-1096.
references: Buer CS, Sukumar P, Muday GK. 2006. Ethylene modulates flavonoid accumulation and gravitropic responses in roots of Arabidopsis. Plant Physiology 140: 1384-1396.
references: Darwin C, Darwin F. 1880. The power of movement in plants. London, UK: John Murray.
references: De Smet I, Tetsumura T, De Rybel B, Frei dit Frey N, Laplaze L, Casimiro I, Swarup R, Naudts M, Vanneste S, Audenaert D, Inzé D, Bennett MJ, Beeckman T. 2007. Auxin-dependent regulation of lateral root positioning in the basal meristem of Arabidopsis. Development 134: 681-690.
references: Doerner P. 2003. Plant meristems: a merry-go-round of signals. Current Biology 13: R368-R374.
references: Eapen D, Barroso ML, Ponce G, Campos ME, Cassab GI. 2005. Hydrotropism: root growth responses to water. Trends in Plant Science 10: 44-50.
references: Edelmann HG, Roth U. 2006. Gravitropic plant growth regulation and ethylene: an unsought cardinal coordinate for a disused model. Protoplasma 229: 183-191.
references: Furutani I, Watanabe Y, Prieto R, Masukawa M, Suzuki K, Naoi K, Thitamadee S, Shikanai T, Hashimoto T. 2000. The SPIRAL genes are required for directional control of cell elongation in Arabidopsis thaliana. Development 127: 4443-4453.
references: Hashimoto T. 2002. Molecular genetic analysis of left-right handedness in plants. Philosophical Transactions of the Royal Society of London B Biological Science 357: 799-808.
references: Hobe M, Muller R, Grunewald M, Brand U, Simon R. 2003. Loss of CLE40, a protein functionally equivalent to the stem cell restricting signal CLV3, enhances root waving in Arabidopsis. Development Genes and Evolution 213: 371-381.
references: Iino M. 2006. Toward understanding the ecological functions of tropisms: interactions among and effects of light on tropisms. Current Opinions in Plant Biology 9: 89-93.
references: Joo JH, Yoo HJ, Hwang I, Lee JS, Nam KH, Bae YS. 2005. Auxin-induced reactive oxygen species production requires the activation of phosphatidylinositol 3-kinase. FEBS Letters 579: 1243-1248.
references: Kimura M, Kagawa T. 2006. Phototropin and light-signaling in phototropism. Current Opinions in Plant Biology 9: 503-508.
references: Lee JS, Mulkey TJ, Evans ML. 1984. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors. Planta 160: 536-543.
references: Lehman A, Black R, Ecker JR. 1996. HOOKLESS1, an ethylene response gene, is required for differential cell elongation in the Arabidopsis hypocotyl. Cell 85: 183-194.
references: Maher E, Martindale S. 1980. Mutants of Arabidopsis thaliana with altered responses to auxin and growth. Biochemistry and Genetics 18: 1041-1053.
references: Migliaccio F, Piconese S. 2001. Spiralizations and tropisms in Arabidopsis roots. Trends in Plant Science 6: 561-565.
references: Mochizuki S, Harada A, Inada S, Sugimoto-Shirasu K, Stacey N, Wada T, Ishiguro S, Okada K, Sakai T. 2005. The Arabidopsis WAVY GROWTH 2 protein modulates root bending in response to environmental stimuli. Plant Cell 17: 537-547.
references: Molas ML, Kiss JZ, Correll MJ. 2006. Gene profiling of the red light signalling pathways in roots. Journal of Experimental Botany 57: 3217-3229.
references: Muday GK. 2001. Auxins and tropisms. Journal of Plant Growth Regulation 20: 226-243.
references: Mullen JL, Turk E, Johnson K, Wolverton C, Ishikawa H, Simmons C, Soll D, Evans ML. 1998. Root-growth behavior of the Arabidopsis mutant rgr1. Roles of gravitropism and circumnutation in the waving/coiling phenomenon. Plant Physiology 118: 1139-1145.
references: Murashige T, Skoog F. 1962. A revised medium for rapid growth and bioessays with tobacco tissue cultures. Physiologia Plantarum 15: 473-497.
references: Okada K, Shimura Y. 1990. Reversible root tip rotation in Arabidopsis seedlings induced by obstacle-touching stimulus. Science 250: 274-276.
references: Oyama T, Shimura Y, Okada K. 1997. The Arabidopsis HY5 gene encodes a bZIP protein that regulates stimulus-induced development of root and hypocotyl. Genes and Development 11: 2983-2995.
references: Rashotte AM, Brady SR, Reed RC, Ante SJ, Muday GK. 2000. Basipetal auxin transport is required for gravitropism in roots of Arabidopsis. Plant Physiology 122: 481-490.
references: Rutherford R, Masson PH. 1996. Arabidopsis thaliana sku mutant seedlings show exaggerated surface-dependent alteration in root growth vector. Plant Physiology 111: 987-998.
references: Rutherford R, Gallois P, Masson PH. 1998. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces. Plant Journal 16: 145-154.
references: Santner AA, Watson JC. 2006. The WAG1 and WAG2 protein kinases negatively regulate root waving in Arabidopsis. Plant Journal 45: 752-764.
references: Sedbrook JC, Ehrhardt DW, Fisher SE, Scheible WR, Somerville CR. 2004. The Arabidopsis sku6/spiral1 gene encodes a plus end-localized microtubule-interacting protein involved in directional cell expansion. Plant Cell 16: 1506-1520.
references: Simmons C, Migliaccio F, Masson P, Caspar T, Soll D. 1995. A novel root gravitropism mutant of Arabidopsis thaliana exhibiting altered auxin physiology. Physiologia Plantarum 93: 790-798.
references: Takahashi N, Goto N, Okada K, Takahashi H. 2002. Hydrotropism in abscisic acid, wavy, and gravitropic mutants of Arabidopsis thaliana. Planta 216: 203-211.
references: Thitamadee S, Tuchihara K, Hashimoto T. 2002. Microtubule basis for left-handed helical growth in Arabidopsis. Nature 417: 193-196.
references: Thompson MV, Holbrook NM. 2004. Root-gel interactions and the root waving behavior of Arabidopsis. Plant Physiology 135: 1822-1837.
references: Yuen CY, Sedbrook JC, Perrin RM, Carroll KL, Masson PH. 2005. Loss-of-function mutations of ROOT HAIR DEFECTIVE3 suppress root waving, skewing, and epidermal cell file rotation in Arabidopsis. Plant Physiology 138: 701-714.