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Auxin and other signals on the move in plants

Abstract

As multicellular organisms, plants, like animals, use endogenous signaling molecules to coordinate their own physiology and development. To compensate for the absence of a cardiovascular system, plants have evolved specialized transport pathways to distribute signals and nutrients. The main transport streams include the xylem flow of the nutrients from the root to the shoot and the phloem flow of materials from the photosynthetic active tissues. These long-distance transport processes are complemented by several intercellular transport mechanisms (apoplastic, symplastic and transcellular transport). A prominent example of transcellular flow is transport of the phytohormone auxin within tissues. The process is mediated by influx and efflux carriers, whose polar localization in the plasma membrane determines the directionality of the flow. This polar auxin transport generates auxin maxima and gradients within tissues that are instrumental in the diverse regulation of various plant developmental processes, including embryogenesis, organogenesis, vascular tissue formation and tropisms.

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Figure 1: Phloem and xylem transport in plants.
Figure 2: Three pathways for intercellular transport.
Figure 3: Boron transport as an example that combines different transport mechanisms.
Figure 4: Phloem-based transport and chemiosmotic model for polar auxin transport.
Figure 5: Dynamic PIN polar localization during embryo and root development.

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References

  1. Valladares, F., Gianoli, E. & Gómez, J. Ecological limits to plant phenotypic plasticity. New Phytol. 176, 749–763 (2007).

    PubMed  Google Scholar 

  2. Alabadí, D. & Blázquez, M.A. Molecular interactions between light and hormone signaling to control plant growth. Plant Mol. Biol. 69, 409–417 (2009).

    PubMed  Google Scholar 

  3. Kim, G.T., Yano, S., Kozuka, T. & Tsukaya, H. Photomorphogenesis of leaves: shade-avoidance and differentiation of sun and shade leaves. Photochem. Photobiol. Sci. 4, 770–774 (2005).

    CAS  PubMed  Google Scholar 

  4. Esmon, C.A., Pedmale, U.V. & Liscum, E. Plant tropisms: providing the power of movement to a sessile organism. Int. J. Dev. Biol. 49, 665–674 (2005).

    CAS  PubMed  Google Scholar 

  5. Gomez-Roldan, V. et al. Strigolactone inhibition of shoot branching. Nature 455, 189–194 (2008).

    CAS  PubMed  Google Scholar 

  6. Umehara, M. et al. Inhibition of shoot branching by new terpenoid plant hormones. Nature 455, 195–200 (2008).

    CAS  PubMed  Google Scholar 

  7. Bishopp, A., Mähönen, A.P. & Helariutta, Y. Signs of change: hormone receptors that regulate plant development. Development 133, 1857–1869 (2006).

    CAS  PubMed  Google Scholar 

  8. Berger, S. Jasmonate-related mutants of Arabidopsis as tools for studying stress signaling. Planta 214, 497–504 (2002).

    CAS  PubMed  Google Scholar 

  9. Spoel, S.H. & Dong, X. Making sense of hormone crosstalk during plant immune responses. Cell Host Microbe 3, 348–351 (2008).

    CAS  PubMed  Google Scholar 

  10. Aloni, R., Aloni, E., Langhans, M. & Ullrich, C. Role of auxin in regulating Arabidopsis flower development. Planta 223, 315–328 (2006).

    CAS  PubMed  Google Scholar 

  11. Cecchetti, V., Altamura, M.M., Falasca, G., Costantino, P. & Cardarelli, M. Auxin regulates Arabidopsis anther dehiscence, pollen maturation, and filament elongation. Plant Cell 20, 1760–1774 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  12. Friml, J. et al. Efflux-dependent auxin gradients establish the apical-basal axis of Arabidopsis. Nature 426, 147–153 (2003).

    CAS  PubMed  Google Scholar 

  13. Reinhardt, D. Vascular patterning: more than just auxin? Curr. Biol. 13, R485–R487 (2003).

    CAS  PubMed  Google Scholar 

  14. Reinhardt, D. Phyllotaxis—a new chapter in an old tale about beauty and magic numbers. Curr. Opin. Plant Biol. 8, 487–493 (2005).

    CAS  PubMed  Google Scholar 

  15. Benková, E. et al. Local, efflux-dependent auxin gradients as a common module for plant organ formation. Cell 115, 591–602 (2003).

    PubMed  Google Scholar 

  16. Dinneny, J.R. & Yanofsky, M.F. Vascular patterning: xylem or phloem? Curr. Biol. 14, R112–R114 (2004).

    CAS  PubMed  Google Scholar 

  17. Ding, B., Itaya, A. & Qi, Y. Symplasmic protein and RNA traffic: regulatory points and regulatory factors. Curr. Opin. Plant Biol. 6, 596–602 (2003).

    CAS  PubMed  Google Scholar 

  18. Maule, A.J. Plasmodesmata: structure, function and biogenesis. Curr. Opin. Plant Biol. 11, 680–686 (2008).

    CAS  PubMed  Google Scholar 

  19. Hose, E., Clarkson, D.T., Steudle, E., Schreiber, L. & Hartung, W. The exodermis: a variable apoplastic barrier. J. Exp. Bot. 52, 2245–2264 (2001).

    CAS  PubMed  Google Scholar 

  20. Amtmann, A. & Blatt, M.R. Regulation of macronutrient transport. New Phytol. 181, 35–52 (2009).

    CAS  PubMed  Google Scholar 

  21. Clapham, D.E. Calcium signaling. Cell 131, 1047–1058 (2007).

    CAS  PubMed  Google Scholar 

  22. Scofield, G.N. et al. The role of the sucrose transporter, OsSUT1, in germination and early seedling growth and development of rice plants. J. Exp. Bot. 58, 483–495 (2007).

    CAS  PubMed  Google Scholar 

  23. Lucas, W.J. Plant viral movement proteins: agents for cell-to-cell trafficking of viral genomes. Virology 344, 169–184 (2006).

    CAS  PubMed  Google Scholar 

  24. Kankanala, P., Czymmek, K. & Valent, B. Roles for rice membrane dynamics and plasmodesmata during biotrophic invasion by the blast fungus. Plant Cell 19, 706–724 (2007).

    CAS  PubMed  PubMed Central  Google Scholar 

  25. Jiang, F. & Hartung, W. Long-distance signalling of abscisic acid (ABA): the factors regulating the intensity of the ABA signal. J. Exp. Bot. 59, 37–43 (2008).

    CAS  PubMed  Google Scholar 

  26. Hirose, N. et al. Regulation of cytokinin biosynthesis, compartmentalization and translocation. J. Exp. Bot. 59, 75–83 (2008).

    CAS  PubMed  Google Scholar 

  27. Booker, J. et al. MAX1 encodes a cytochrome P450 family member that acts downstream of MAX3/4 to produce a carotenoid-derived branch-inhibiting hormone. Dev. Cell 8, 443–449 (2005).

    CAS  PubMed  Google Scholar 

  28. Cambridge, A.P. & Morris, D.A. Transfer of exogenous auxin from the phloem to the polar auxin transport pathway in pea (Pisum sativum L.). Planta 199, 583–588 (1996).

    CAS  Google Scholar 

  29. Lough, T.J. & Lucas, W.J. Integrative plant biology: role of phloem long-distance macromolecular trafficking. Annu. Rev. Plant Biol. 57, 203–232 (2006).

    CAS  PubMed  Google Scholar 

  30. Giakountis, A. & Coupland, G. Phloem transport of flowering signals. Curr. Opin. Plant Biol. 11, 687–694 (2008).

    CAS  PubMed  Google Scholar 

  31. Fukuda, H. Signals that control plant vascular cell differentiation. Nat. Rev. Mol. Cell Biol. 5, 379–391 (2004).

    CAS  PubMed  Google Scholar 

  32. Sauer, M. et al. Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity. Genes Dev. 20, 2902–2911 (2006).

    CAS  PubMed  PubMed Central  Google Scholar 

  33. Sachs, T. Integrating cellular and organismic aspects of vascular differentiation. Plant Cell Physiol. 41, 649–656 (2000).

    CAS  PubMed  Google Scholar 

  34. Mähönen, A.P. et al. Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. Science 311, 94–98 (2006).

    PubMed  Google Scholar 

  35. Choe, S. et al. The Arabidopsis dwf7/ste1 mutant is defective in the delta7 sterol C-5 desaturation step leading to brassinosteroid biosynthesis. Plant Cell 11, 207–221 (1999).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Tester, M. & Leigh, R.A. Partitioning of nutrient transport processes in roots. J. Exp. Bot. 52, 445–457 (2001).

    CAS  PubMed  Google Scholar 

  37. Zimmermann, H.M., Hartmann, K., Schreiber, L. & Steudle, E. Chemical composition of apoplastic transport barriers in relation to radial hydraulic conductivity of corn roots (Zea mays L.). Planta 210, 302–311 (2000).

    CAS  PubMed  Google Scholar 

  38. Symons, G.M., Ross, J.J., Jager, C.E. & Reid, J.B. Brassinosteroid transport. J. Exp. Bot. 59, 17–24 (2008).

    CAS  PubMed  Google Scholar 

  39. Rojo, E., Sharma, V.K., Kovaleva, V., Raikhel, N.V. & Fletcher, J.C. CLV3 is localized to the extracellular space, where it activates the Arabidopsis CLAVATA stem cell signaling pathway. Plant Cell 14, 969–977 (2002).

    CAS  PubMed  PubMed Central  Google Scholar 

  40. Kim, I., Cho, E., Crawford, K., Hempel, F.D. & Zambryski, P.C. Cell-to-cell movement of GFP during embryogenesis and early seedling development in Arabidopsis. Proc. Natl. Acad. Sci. USA 102, 2227–2231 (2005).

    CAS  PubMed  PubMed Central  Google Scholar 

  41. Kim, I., Kobayashi, K., Cho, E. & Zambryski, P.C. Subdomains for transport via plasmodesmata corresponding to the apical-basal axis are established during Arabidopsis embryogenesis. Proc. Natl. Acad. Sci. USA 102, 11945–11950 (2005).

    CAS  PubMed  PubMed Central  Google Scholar 

  42. Sauer, N. Molecular physiology of higher plant sucrose transporters. FEBS Lett. 581, 2309–2317 (2007).

    CAS  PubMed  Google Scholar 

  43. Dunoyer, P., Himber, C., Ruiz-Ferrer, V., Alioua, A. & Voinnet, O. Intra- and intercellular RNA interference in Arabidopsis thaliana requires components of the microRNA and heterochromatic silencing pathways. Nat. Genet. 39, 848–856 (2007).

    CAS  PubMed  Google Scholar 

  44. Kurata, T. et al. Cell-to-cell movement of the CAPRICE protein in Arabidopsis root epidermal cell differentiation. Development 132, 5387–5398 (2005).

    CAS  PubMed  Google Scholar 

  45. Lee, J.Y. et al. Transcriptional and posttranscriptional regulation of transcription factor expression in Arabidopsis roots. Proc. Natl. Acad. Sci. USA 103, 6055–6060 (2006).

    CAS  PubMed  PubMed Central  Google Scholar 

  46. Lucas, W.J. et al. Selective trafficking of KNOTTED1 homeodomain protein and its mRNA through plasmodesmata. Science 270, 1980–1983 (1995).

    CAS  PubMed  Google Scholar 

  47. Nakajima, K., Sena, G., Nawy, T. & Benfey, P.N. Intercellular movement of the putative transcription factor SHR in root patterning. Nature 413, 307–311 (2001).

    CAS  PubMed  Google Scholar 

  48. Crawford, K.M. & Zambryski, P.C. Non-targeted and targeted protein movement through plasmodesmata in leaves in different developmental and physiological states. Plant Physiol. 125, 1802–1812 (2001).

    CAS  PubMed  PubMed Central  Google Scholar 

  49. Buchner, P., Takahashi, H. & Hawkesford, M.J. Plant sulphate transporters: co-ordination of uptake, intracellular and long-distance transport. J. Exp. Bot. 55, 1765–1773 (2004).

    CAS  PubMed  Google Scholar 

  50. Loqué, D. & von Wirén, N. Regulatory levels for the transport of ammonium in plant roots. J. Exp. Bot. 55, 1293–1305 (2004).

    PubMed  Google Scholar 

  51. Fujii, H., Chiou, T.J., Lin, S.I., Aung, K. & Zhu, J. A miRNA involved in phosphate-starvation response in Arabidopsis. Curr. Biol. 15, 2038–2043 (2005).

    CAS  PubMed  Google Scholar 

  52. Peng, M., Hannam, C., Gu, H., Bi, Y.M. & Rothstein, S.J. A mutation in NLA, which encodes a RING-type ubiquitin ligase, disrupts the adaptability of Arabidopsis to nitrogen limitation. Plant J. 50, 320–337 (2007).

    CAS  PubMed  Google Scholar 

  53. Takano, J., Miwa, K. & Fujiwara, T. Boron transport mechanisms: collaboration of channels and transporters. Trends Plant Sci. 13, 451–457 (2008).

    CAS  PubMed  Google Scholar 

  54. Miller, A.J., Fan, X., Shen, Q. & Smith, S.J. Amino acids and nitrate as signals for the regulation of nitrogen acquisition. J. Exp. Bot. 59, 111–119 (2008).

    CAS  PubMed  Google Scholar 

  55. Kasai, M. Regulation of leaf photosynthetic rate correlating with leaf carbohydrate status and activation state of Rubisco under a variety of photosynthetic source/sink balances. Physiol. Plant. 134, 216–226 (2008).

    CAS  PubMed  Google Scholar 

  56. Paul, M.J. & Pellny, T.K. Carbon metabolite feedback regulation of leaf photosynthesis and development. J. Exp. Bot. 54, 539–547 (2003).

    CAS  PubMed  Google Scholar 

  57. Camacho-Cristóbal, J.J. & González-Fontes, A. Boron deficiency decreases plasmalemma H+-ATPase expression and nitrate uptake, and promotes ammonium assimilation into asparagine in tobacco roots. Planta 226, 443–451 (2007).

    PubMed  Google Scholar 

  58. Mérigout, P. et al. Physiological and transcriptomic aspects of urea uptake and assimilation in Arabidopsis plants. Plant Physiol. 147, 1225–1238 (2008).

    PubMed  PubMed Central  Google Scholar 

  59. Takano, J. et al. The Arabidopsis major intrinsic protein NIP5;1 is essential for efficient boron uptake and plant development under boron limitation. Plant Cell 18, 1498–1509 (2006).

    PubMed  PubMed Central  Google Scholar 

  60. Tanaka, M., Wallace, I.S., Takano, J., Roberts, D.M. & Fujiwara, T. NIP6;1 is a boric acid channel for preferential transport of boron to growing shoot tissues in Arabidopsis. Plant Cell 20, 2860–2875 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  61. Miwa, K. et al. Plants tolerant of high boron levels. Science 318, 1417 (2007).

    CAS  PubMed  Google Scholar 

  62. Darwin, C. The Power of Movement in Plants (John Murray, London, 1880).

    Google Scholar 

  63. Went, F.W. & Thimann, K.V. Phytohormones (Macmillan, New York, 1937).

    Google Scholar 

  64. Ulmasov, T., Murfett, J., Hagen, G. & Guilfoyle, T.J. Aux/IAA proteins repress expression of reporter genes containing natural and highly active synthetic auxin response elements. Plant Cell 9, 1963–1971 (1997).

    CAS  PubMed  PubMed Central  Google Scholar 

  65. Dubrovsky, J.G. et al. Auxin acts as a local morphogenetic trigger to specify lateral root founder cells. Proc. Natl. Acad. Sci. USA 105, 8790–8794 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  66. Heisler, M.G. et al. Patterns of auxin transport and gene expression during primordium development revealed by live imaging of the inflorescence meristem. Curr. Biol. 15, 1899–1911 (2005).

    CAS  PubMed  Google Scholar 

  67. Nemhauser, J.L., Feldman, L.J. & Zambryski, P.C. Auxin and ETTIN in Arabidopsis gynoecium morphogenesis. Development 127, 3877–3888 (2000).

    CAS  PubMed  Google Scholar 

  68. Sabatini, S. et al. An auxin-dependent distal organizer of pattern and polarity in the Arabidopsis root. Cell 99, 463–472 (1999).

    CAS  PubMed  Google Scholar 

  69. Friml, J. et al. AtPIN4 mediates sink-driven auxin gradients and root patterning in Arabidopsis. Cell 108, 661–673 (2002).

    CAS  PubMed  Google Scholar 

  70. Sorefan, K. et al. A regulated auxin minimum is required for seed dispersal in Arabidopsis. Nature advance online publication, doi:10.1038/nature07875 (2009).

  71. Mockaitis, K. & Estelle, M. Auxin receptors and plant development: a new signaling paradigm. Annu. Rev. Cell Dev. Biol. 24, 55–80 (2008).

    CAS  PubMed  Google Scholar 

  72. Friml, J. et al. A PINOID-dependent binary switch in apical-basal PIN polar targeting directs auxin efflux. Science 306, 862–865 (2004).

    CAS  PubMed  Google Scholar 

  73. Cheng, Y., Dai, X. & Zhao, Y. Auxin synthesized by the YUCCA flavin monooxygenases is essential for embryogenesis and leaf formation in Arabidopsis. Plant Cell 19, 2430–2439 (2007).

    CAS  PubMed  PubMed Central  Google Scholar 

  74. Cheng, Y., Dai, X. & Zhao, Y. Auxin biosynthesis by the YUCCA flavin monooxygenases controls the formation of floral organs and vascular tissues in Arabidopsis. Genes Dev. 20, 1790–1799 (2006).

    CAS  PubMed  PubMed Central  Google Scholar 

  75. Stepanova, A.N. et al. TAA1-mediated auxin biosynthesis is essential for hormone crosstalk and plant development. Cell 133, 177–191 (2008).

    CAS  PubMed  Google Scholar 

  76. Vanneste, S., & Friml, J. Auxin: a trigger for change in plant development. Cell 136, 1005–1016 (2009).

    CAS  PubMed  Google Scholar 

  77. Rubery, P.H. & Sheldrake, A.R. Carrier-mediated auxin transport. Planta 118, 101–121 (1974).

    CAS  PubMed  Google Scholar 

  78. Raven, J. Transport of indolacetic acid in plant cells in relation to pH and electrical potential gradients, and its ignificaance for polar IAA transport. New Phytol. 74, 163–172 (1975).

    CAS  Google Scholar 

  79. Friml, J., Wiśniewska, J., Benková, E., Mendgen, K. & Palme, K. Lateral relocation of auxin efflux regulator PIN3 mediates tropism in Arabidopsis. Nature 415, 806–809 (2002).

    PubMed  Google Scholar 

  80. Gälweiler, L. et al. Regulation of polar auxin transport by AtPIN1 in Arabidopsis vascular tissue. Science 282, 2226–2230 (1998).

    PubMed  Google Scholar 

  81. Müller, A. et al. AtPIN2 defines a locus of Arabidopsis for root gravitropism control. EMBO J. 17, 6903–6911 (1998).

    PubMed  PubMed Central  Google Scholar 

  82. Wis´niewska, J. et al. Polar PIN localization directs auxin flow in plants. Science 312, 858–860 (2006).

    Google Scholar 

  83. Bennett, M.J. et al. Arabidopsis AUX1 gene: a permease-like regulator of root gravitropism. Science 273, 948–950 (1996).

    CAS  PubMed  Google Scholar 

  84. Yang, Y., Hammes, U.Z., Taylor, C.G., Schachtman, D.P. & Nielsen, E. High-affinity auxin transport by the AUX1 influx carrier protein. Curr. Biol. 16, 1123–1127 (2006).

    CAS  PubMed  Google Scholar 

  85. Swarup, R. et al. Localization of the auxin permease AUX1 suggests two functionally distinct hormone transport pathways operate in the Arabidopsis root apex. Genes Dev. 15, 2648–2653 (2001).

    CAS  PubMed  PubMed Central  Google Scholar 

  86. Bainbridge, K. et al. Auxin influx carriers stabilize phyllotactic patterning. Genes Dev. 22, 810–823 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  87. Swarup, K. et al. The auxin influx carrier LAX3 promotes lateral root emergence. Nat. Cell Biol. 10, 946–954 (2008).

    CAS  PubMed  Google Scholar 

  88. Petrášek, J. PIN proteins perform a rate-limiting function in cellular auxin efflux. Science 312, 914–918 (2006).

    PubMed  Google Scholar 

  89. Geisler, M. et al. Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PGP transporter AtPGP1. Plant J. 44, 179–194 (2005).

    CAS  PubMed  Google Scholar 

  90. Cho, M., Lee, S.H. & Cho, H.-T. P-glycoprotein4 displays auxin efflux transporter-like action in Arabidopsis root hair cells and tobacco cells. Plant Cell 19, 3930–3943 (2007).

    CAS  PubMed  PubMed Central  Google Scholar 

  91. Mravec, J. et al. Interaction of PIN and PGP transport mechanisms in auxin distribution-dependent development. Development 135, 3345–3354 (2008).

    CAS  PubMed  Google Scholar 

  92. Blakeslee, J.J. et al. Interactions among PIN-FORMED and P-glycoprotein auxin transporters in Arabidopsis. Plant Cell 19, 131–147 (2007).

    CAS  PubMed  PubMed Central  Google Scholar 

  93. Titapiwatanakun, B. et al. ABCB19/PGP19 stabilises PIN1 in membrane microdomains in Arabidopsis. Plant J. 57, 27–44 (2009).

    CAS  PubMed  Google Scholar 

  94. Kleine-Vehn, J. & Friml, J. Polar targeting and endocytic recycling in auxin-dependent plant development. Annu. Rev. Cell Dev. Biol. 24, 447–473 (2008).

    CAS  PubMed  Google Scholar 

  95. Tanaka, H., Dhonukshe, P., Brewer, P. & Friml, J. Spatiotemporal asymmetric auxin distribution: a means to coordinate plant development. Cell. Mol. Life Sci. 63, 2738–2754 (2006).

    CAS  PubMed  Google Scholar 

  96. Michniewicz, M. et al. Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux. Cell 130, 1044–1056 (2007).

    CAS  PubMed  Google Scholar 

  97. Dhonukshe, P. et al. Generation of cell polarity in plants links endocytosis, auxin distribution and cell fate decisions. Nature 456, 962–966 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  98. Harrison, B.R. & Masson, P. ARL2, ARG1 and PIN3 define a gravity signal transduction pathway in root statocytes. Plant J. 53, 380–392 (2008).

    CAS  PubMed  Google Scholar 

  99. Abas, L. et al. Intracellular trafficking and proteolysis of the Arabidopsis auxin-efflux facilitator PIN2 are involved in root gravitropism. Nat. Cell Biol. 8, 249–256 (2006).

    CAS  PubMed  Google Scholar 

  100. McCormick, A.J., Cramer, M.D. & Watt, D.A. Changes in photosynthetic rates and gene expression of leaves during a source-sink perturbation in sugarcane. Ann. Bot. (Lond.) 101, 89–102 (2008).

    CAS  Google Scholar 

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Acknowledgements

We thank E. Meyerowitz for providing seeds of the DR5rev:N7:VENUS, S. Vanneste for providing material for Figure 5 and M. De Cock for help in preparing the manuscript. The authors are supported by the FWO (Fonds voor Wetenschappelijk Onderzoek).

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Robert, H., Friml, J. Auxin and other signals on the move in plants. Nat Chem Biol 5, 325–332 (2009). https://doi.org/10.1038/nchembio.170

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