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TOUCH ME – ‘Touch’ genes in the micropylar endosperm

  • Hiroyuki Nonogaki (a1)


The micropylar region of endosperm (ME) is a physical barrier to radicle emergence in seeds of many different species, including tomato (Solanum lycopersicum) and Arabidopsis thaliana. ME is thought to be weakened through cell wall-modifying proteins, and this is supported by transcriptome data showing enrichment of cell wall-associated genes in ME. Gibberellin and ethylene have been suggested to be involved in induction of these genes in ME. However, mechanisms underlying this critical event for germination still remain elusive. In addition to hormonal regulation of ME weakening, recent data from high-throughput analyses suggested that it might be important for the radicle tip to ‘touch’ ME (or mechanosensing), in terms of ME-specific gene induction. This emerging hypothesis can be integrated with previous hypotheses about hormonal regulation of ME-specific gene expression in seeds.


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Belin, C.andLopez-Molina, L. (2010) Endosperm rupture as a model for lateral root emergence in Arabidopsis? Plant Signaling Behavior 5, 564566.
Bewley, J.D., Bradford, K.J., Hilhorst, H.W.M. and Nonogaki, H. (2013) Seeds: Physiology of development, germination and dormancy. New York, Springer.
Braam, I. (2005) In touch: plant responses to mechanical stimuli. New Phytologist 165, 373389.
Chen, F. and Bradford, K.J. (2000) Expression of an expansin is associated with endosperm weakening during tomato seed germination. Plant Physiology 124, 12651274.
Chen, F., Dahal, P. and Bradford, K.J. (2001) Two tomato expansin genes show divergent expression and localization in embryos during seed development and germination. Plant Physiology 127, 928936.
Debeaujon, I., Leon-Kloosterziel, K.M. and Koornneef, M. (2000) Influence of the testa on seed dormancy, germination, and longevity in arabidopsis. Plant Physiology 122, 403414.
Debeaujon, I., Lepiniec, L., Pourcel, L. and Routaboul, J.M. (2007) Seed coat development and dormancy. pp. 2549in Bradford, K.J.; Nonogaki, H. (Eds) Seed development, dormancy and germination. Oxford, Blackwell Publishing.
Dekkers, B.J., Pearce, S., Van Bolderen-Veldkamp, R.P., Marshall, A., Widera, P., Gilbert, J., Drost, H.G., Bassel, G.W., Muller, K., King, J.R., Wood, A.T., Grosse, I., Quint, M., Krasnogor, N., Leubner-Metzger, G., Holdsworth, M.J. and Bentsink, L. (2013) Transcriptional dynamics of two seed compartments with opposing roles in Arabidopsis seed germination. Plant Physiology 163, 205215.
Groot, S.P.C. and Karssen, C.M. (1987) Gibberellins regulate seed germination in tomato by endosperm weakening: A study with gibberellin-deficient mutants. Planta 171, 525531.
Ito, Y., Nakanomyo, I., Motose, H., Iwamoto, K., Sawa, S., Dohmae, N. and Fukuda, H. (2006) Dodeca-CLE peptides as suppressors of plant stem cell differentiation. Science 313, 842845.
Johnson, P.R. and Ecker, J.R. (1998) The ethylene gas signal transduction pathway: A molecular perspective. Annual Review of Genetics 32, 227254.
Kondo, T., Sawa, S., Kinoshita, A., Mizuno, S., Kakimoto, T., Fukuda, H. and Sakagami, Y. (2006) A plant peptide encoded by CLV3 identified by in situ MALDI-TOF MS analysis. Science 313, 845848.
Kumpf, R.P., Shi, C.L., Larrieu, A., Sto, I.M., Butenko, M.A., Peret, B., Riiser, E.S., Bennett, M.J. and Aalen, R.B. (2013) Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence. Proceedings of the National Academy of Sciences USA 110, 52355240.
Lee, D., Polisensky, D.H. and Braam, J. (2005) Genome-wide identification of touch- and darkness-regulated arabidopsis genes: A focus on calmodulin-like and XTH genes. New Phytologist 165, 429444.
Lee, K.J., Dekkers, B.J., Steinbrecher, T., Walsh, C.T., Bacic, A., Bentsink, L., Leubner-Metzger, G. and Knox, J.P. (2012) Distinct cell wall architectures in seed endosperms in representatives of the Brassicaceae and Solanaceae. Plant Physiology 160, 15511566.
Lee, K.P., Piskurewicz, U., Turečková, V., Strnad, M. and Lopez-Molina, L. (2010) A seed coat bedding assay shows that RGL2-dependent release of abscisic acid by the endosperm controls embryo growth in arabidopsis dormant seeds. Proceedings of the National Academy of Sciences USA 107, 1910819113.
Linkies, A., Muller, K., Morris, K., Tureckova, V., Wenk, M., Cadman, C.S.C., Corbineau, F., Strnad, M., Lynn, J.R., Finch-Savage, W.E. and Leubner-Metzger, G. (2009) Ethylene interacts with abscisic acid to regulate endosperm rupture during germination: a comparative approach using Lepidium sativum and Arabidopsis thaliana. The Plant Cell 21, 38033822.
Liu, P.P., Koizuka, N., Homrichhausen, T.M., Hewitt, J.R., Martin, R.C. and Nonogaki, H. (2005a) Large-scale screening of Arabidopsis enhancer-trap lines for seed germination-associated genes. The Plant Journal 41, 936944.
Liu, P.P., Koizuka, N., Martin, R.C. and Nonogaki, H. (2005b) The Bme3 (Blue Micropylar End 3) Gata zinc finger transcription factor is a positive regulator of Arabidopsis seed germination. The Plant Journal 44, 960971.
Liu, P.-P., Montgomery, T.A., Fahlgren, N., Kasschau, K.D., Nonogaki, H. and Carrington, J.C. (2007) Repression of AUXIN RESPONSE FACTOR10 by microRNA160 is critical for seed germination and post-germination stages. The Plant Journal 52, 133146.
Martinez-Andujar, C., Pluskota, W.E., Bassel, G.W., Asahina, M., Pupel, P., Nguyen, T.T., Takeda-Kamiya, N., Toubiana, D., Bai, B., Gorecki, R.J., Fait, A., Yamaguchi, S. and Nonogaki, H. (2012) Mechanisms of hormonal regulation of endosperm cap-specific gene expression in tomato seeds. The Plant Journal 71, 575586.
Muller, K., Tintelnot, S. and Leubner-Metzger, G. (2006) Endosperm-limited Brassicaceae seed germination: abscisic acid inhibits embryo-induced endosperm weakening of Lepidium sativum (cress) and endosperm rupture of cress and Arabidopsis thaliana. Plant and Cell Physiology 47, 864877.
Nonogaki, H. (2008) Repression of transcription factors by microRNA during seed germination and postgermination: Another level of molecular repression in seeds? Plant Signaling and Behavior 3, 6567.
Nonogaki, H. and Morohashi, Y. (1996) An endo-β-mannanase develops exclusively in the micropylar endosperm of tomato seeds prior to radicle emergence. Plant Physiology 110, 555559.
Nonogaki, H., Gee, O.H. and Bradford, K.J. (2000) A germination-specific endo-β-mannanase gene is expressed in the micropylar endosperm cap of tomato seeds. Plant Physiology 123, 12351246.
Opsahl-Ferstad, H.-G., Deunff, E.L., Dumas, C. and Rogowsky, P.M. (1997) ZmESR, a novel endosperm-specific gene expressed in a restricted region around the maize embryo. The Plant Journal 12, 235246.
Piskurewicz, U., Jikumaru, Y., Kinoshita, N., Nambara, E., Kamiya, Y. and Lopez-Molina, L. (2008) The gibberellic acid signaling repressor RGL2 inhibits Arabidopsis seed germination by stimulating abscisic acid synthesis and ABI5 activity. The Plant Cell 20, 27292745.
Seo, M., Nambara, E., Choi, G. and Yamaguchi, S. (2009) Interaction of light and hormone signals in germinating seeds. Plant Molecular Biology 69, 463472.
Sitrit, Y., Hadfield, K.A., Bennett, A.B., Bradford, K.J. and Downie, A.B. (1999) Expression of a polygalacturonase associated with tomato seed germination. Plant Physiology 121, 419428.
Toorop, P.E., Bewley, J.D. and Hilhorst, H.W.M. (1996) Endo-β-mannanase isoforms are present in the endosperm and embryo of tomato seeds, but are not essentially linked to the completion of germination. Planta 200, 153158.
Watkins, J.T. and Cantliffe, D.J. (1983) Mechanical resistance of the seed coat and endosperm during germination of Capsicum annuum at low temperature. Plant Physiology 72, 146150.


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TOUCH ME – ‘Touch’ genes in the micropylar endosperm

  • Hiroyuki Nonogaki (a1)


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