これまでに多くの植物ホルモンについて、生合成、分解（不活性化）、受容、情報伝達に関わる詳細な制御機構が明らかになりつつありますが、植物ホルモンの輸送については生理的な意味も含めて未解明な点が多く残されています。私たちは、ABA、GA、JAに対する受容体が、それぞれの化合物依存的に特定の制御タンパク質と相互作用する性質を利用し、未知の植物ホルモン輸送体を網羅的に探索する酵母two-hybrid系を確立しました。この手法により、これまでに硝酸やペプチドの輸送体ファミリーとして知られていたNRT1/PTR FAMILY (NPF)タンパク質のいくつかが、 ABA、GA、JAの輸送体として機能することを明らかにしました。また、近年新たな糖輸送体ファミリーとして報告されたSWEETタンパク質のいくつかが、GA輸送体として機能することも明らかにしました。これらの輸送体の詳細な機能解析を進めるとともに、新たな植物ホルモン輸送体の探索を進めています。

植物ホルモンによって引き起こされる生理作用は、植物ホルモンの内生量に大きく依存します。そのため、植物体内における植物ホルモンの内生量を正確に把握することが非常に重要です。私たちは、液体クロマトグラフィー・タンデム質量分析法（LC-MS/MS）を用いて、ABA、GA、JA、IAA、サイトカイニン、サリチル酸などの植物ホルモンの微量定量をおこなっています。また、ナノスプレーチップと呼ばれる先端系約1マイクロメートルの微細なキャピラリーを用いて、顕微鏡下で分取した細胞内容物を直接質量分析することにより、植物ホルモンを一細胞から定量する技術開発にも取り組んでいます。

上記の通り、植物ホルモンが植物の生活環の多くの場面で重要な役割を果たしていることが知られていますが、既知の植物ホルモン以外にも重要な生理活性を持つ化合物が存在すると予想されます。私たちは、酵素や輸送体の機能を欠失した変異体の表現型に着目し、トランスクリプトーム、メタボローム、ケミカルバイオロジーなどの多面的なアプローチを駆使して、植物の成長を制御する新たな生理活性物質の探索を進めています。

種子は乾燥、高温、低温などの過酷な環境を、時には数百年もの間、生きたまま乗り越える事が出来ます。私たちは、植物ホルモンに着目したアプローチのみでなく、シロイヌナズナの野生型系統間における多様性（自然変異・ナチュラルバリエーション）に着目したアプローチで、休眠、発芽、寿命などに関する種子に秘められた特殊な機能の決定に関与する因子の同定を進めています。

関連情報

最近の研究業績

1. Ravid, J., Spitzer-Rimon, B., Takebayashi, Y., Seo, M., Cna'ani, A., Aravena-Calvo, J., Masci, T., Farhi, M., Vainstein, A. (2016) GA as a regulatory link between the showy floral traits color and scent. New Phytol. (in press)
2. Ishimaru, Y., Oikawa, T., Suzuki, T., Takeishi, S., Matsuura H., Takahashi K., Hamamoto, S., Uozumi, N., Shimizu, T., Seo, M., Ohta H., Ueda M. (2017) GTR1 is a jasmonic acid and jasmonoyl-L-isoleucine transporter in Arabidopsis thaliana. Biosci. Biotech. Biochem. 81: 249-255.
3. Nguyen, C.C., Nakaminami, K., Matsui, A., Watanabe, S., Kanno, Y., Seo, M., Seki, M. (2017) Overexpression of oligouridylate binding protein 1b results in ABA hypersensitivity. Plant Signal. Behav. 12: e1282591.
4. Chang, X., Seo, M., Takebayashi, Y., Kamiya, Y., Riemann, M., Nick, P. (2017) Jasmonates are induced by the PAMP flg22 but not the cell death-inducing elicitor Harpin in Vitis rupestris. Protoplasma 254: 271-283.
5. David, L.C., Berquin, P., Kanno, Y., Seo, M., Daniel-Vedele, F., Ferrario-Méry, S. (2016) N availability modulates the role of NPF3.1, a gibberellin transporter, in GA-mediated phenotypes in Arabidopsis. Planta 224: 1351-1328.
6. Takeuchi, J., Okamoto, M., Mega, R., Kanno, Y., Ohnishi, T., Seo, M., Todoroki, Y. (2016) Abscinazole-E3M, a practical inhibitor of abscisic acid 8'-hydroxylase for improving drought tolerance. Sci. Rep. 6: 37060.
7. Kanno, Y., Oikawa, T., Chiba, Y., Ishimaru, Y., Shimizu, T., Sano, N., Koshiba, T., Kamiya, Y., Ueda, M., Seo, M. (2016) AtSWEET13 and AtSWEET14 regulate gibberellin-mediated physiological processes. Nat. Commun. 7: 13245.
8. Seo, M., Kanno, Y., Frey, A., North, H.M. and Marion-Poll, A. (2016) Dissection of Arabidopsis NCED9 promoter regulatory regions reveals a role for ABA synthesized in embryos in the regulation of GA-dependent seed germination. Plant Sci. 246: 91-97.
9. Nagatoshi, Y., Mitsuda, N., Hayashi, M., Inoue, S.I., Okuma, E., Kubo, A., Murata, Y., Seo, M., Saji, H., Kinoshita, T., Ohme-Takagi, M. (2016) GOLDEN 2-LIKE transcription factors for chloroplast development affect ozone tolerance through the regulation of stomatal movement. Proc. Natl. Acad. Sci. USA 113: 4218-4223.
10. Kashiwakura, Y.I., Kobayashi, D., Jikumaru, Y., Takebayashi, Y., Nambara, E., Seo, M., Kamiya, Y., Kushiro, T., Kawakami, N. (2016) Highly sprouting tolerant wheat grain exhibits extreme dormancy and cold imbibition resistant accumulation of abscisic acid. Plant Cell Physiol. 57: 715-732.
11. Sano, N., Rajjou, L., North, H.M., Debeaujon, I., Marion-Poll, A., Seo, M. (2016) Staying Alive: Molecular Aspects of Seed Longevity. Pant Cell Physiol. 57: 660-674.
12. 清水崇史、瀬尾光範 (2016) 一細胞からの植物ホルモン質量分析法、化学と生物 54: 454-456.
13. Maekawa, M., Honoki, R., Ihara, Y., Sato, R., Oikawa, A., Kanno, Y., Ohta, H., Seo, M., Saito, K., Masuda, S., (2015) Impact of the plastidial stringent response in plant growth and stress responses. Nat. Plants 1: 15167.
14. Mega, R., Meguro-Maoka, A., Endo, A., Shimosaka, E., Murayama, S., Nambara, E., Seo, M., Kanno, Y., Abrams, S.R., Sato, Y. (2015) Sustained low abscisic acid levels increase seedling vigor under cold stress in rice (Oryza sativa L.). Sci Rep. 5: 13819.
15. Hauvermale, A.L., Tuttle, K.M., Takebayashi, Y., Seo, M., Steber, C.M. (2015) Loss of Arabidopsis thaliana seed dormancy is associated with increased accumulation of the GID1 GA hormone receptors. Plant Cell Physiol. 56: 1773-85.
16. Ismail, A., Seo, M., Takebayashi, Y., Kamiya, Y., Nick, P. (2015) A balanced JA/ABA status may correlate with adaptation to osmotic stress in Vitis cells. J. Plant Physiol. 185: 57-64.
17. Chiba, Y., Shimizu, T., Miyakawa, S., Kanno, Y., Koshiba, T., Kamiya, Y., Seo, M. (2015) Identification of Arabidopsis NRT1/PTR FAMIRY (NPF) proteins capable of transporting plant hormones. J. Plant Res. 128: 679-686.
18. Shimizu, T., Miyakawa, S., Esaki, T., Mizuno, H., Masujima, T., Koshiba, T., Seo, M. (2015) Live single cell plant hormone analysis by video-mass spectrometry. Plant Cell Physiol. 56: 1287-1296.
19. Mutuku, J.M., Yoshida, S., Shimizu, T., Ichihashi, Y., Wakatake, T., Takahashi, A., Seo, M., Shirasu, K. (2015) The WRKY45-dependent signaling pathway is required for resistance against Striga hermonthica parasitism. Plant Physiol. 168: 1152-63.
20. Saito, H., Oikawa, T., Hamamoto, S., Ishimaru, Y., Kanamori-Sato, M., Sasaki-Sekimoto, Y., Utsumi, T., Chen, J., Kanno, Y., Masuda, S., Kamiya, Y., Seo, M., Uozumi, N., Ueda, M., Ohta, H. (2015) The jasmonate-responsive GTR1 transporter is required for gibberellin-mediated stamen development in Arabidopsis. Nat. Commun. 6: 6095.
21. Kinoshita, A., Ten Hove, C.A., Tabata, R., Yamada, M., Shimizu, N., Ishida, T., Yamaguchi, K., Shigenobu, S., Takebayashi, Y., Iuchi, S., Kobayashi, M., Kurata, T., Wada, T., Seo, M., Hasebe, M., Blilou, I., Fukuda, H., Scheres, B., Heidstra, R., Kamiya, Y., Sawa, S. (2015) A plant U-box protein, PUB4, regulates asymmetric cell division and cell proliferation in the root meristem. Development 142: 444-453.
22. Sasaki, K., Kim, M.H., Kanno, Y., Seo, M., Kamiya, Y., Imai, R. (2015) Arabidopsis COLD SHOCK DOMAIN PROTEIN 2 influences ABA accumulation in seed and negatively regulates germination. Biochem. Biophys. Res. Commun. 456: 380-384.
23. Kinoshita, A., Seo, M., Kamiya, Y., Sawa, S. (2015) Mystery in genetics: PUB4 gives a clue to the complex mechanism of CLV signaling pathway in the shoot apical meristem. Plant Signal. Behav. 10: e1028707.
24. Ismail, A., Seo, M., Takebayashi, Y., Kamiya, Y., Eiche, E., Nick, P. (2014) Salt adaptation requires efficient fine-tuning of jasmonate signaling. Protoplasma 251: 881-898.
25. Takeuchi, J., Okamoto, M., Akiyama, T., Muto, T., Yajima, S., Sue, M., Seo, M., Kanno, Y., Kamo, T., Endo, A., Nambara, E., Hirai, N., Ohnishi, T., Cutler, S.R., Todoroki, Y. (2014) Designed abscisic acid analogs as antagonists of PYL-PP2C receptor interactions. Nat. Chem. Biol. 10: 477-482.
26. Ruduś, I., Terai, H., Shimizu, T., Kojima, H., Hattori, K., Nishimori, Y., Tsukagoshi, H., Kamiya, Y., Seo, M., Nakamura, K., Kępczyński, J., Ishiguro, S. (2014) Wound-induced expression of DEFECTIVE IN ANTHER DEHISCENCE1 and DAD1-like lipase genes is mediated by both CORONATINE INSENSITIVE1-dependent and independent pathways in Arabidopsis thaliana. Plant Cell Rep. 33: 849-860.
27. Hori, K., Maruyama, F., Fujisawa, T., Togashi, T., Yamamoto, N., Seo, M., Sato, S., Yamada, T., Mori, H., Tajima, N., Moriyama, T., Ikeuchi, M., Watanabe, M., Wada, H., Kobayashi, K., Saito, M., Masuda, T., Sasaki-Sekimoto, Y., Mashiguchi, K., Awai, K., Shimojima, M., Masuda, S., Iwai, M., Nobusawa, T., Narise, T., Kondo, S., Saito, H., Sato, R., Murakawa, M., Ihara, Y., Oshima-Yamada, Y., Ohtaka, K., Satoh, M., Sonobe, K., Ishii, M., Ohtani, R., Kanamori-Sato, M., Honoki, R., Miyazaki, D., Mochizuki, H., Umetsu, J., Higashi, K., Shibata, D., Kamiya, Y., Sato, N., Nakamura, Y., Tabata, S., Ida, S., Kurokawa, K., Ohta, H. (2014) Klebsormidium flaccidum genome reveals primary factors for plant terrestrial adaptation. Nat. Commun. 5: 3987
28. Yamaguchi, N., Winter, C.M., Wu, M.F., Kanno, Y., Yamaguchi, A., Seo, M., Wagner, D. (2014) Gibberellin acts positively then negatively to control onset of flower formation in Arabidopsis. Science 344: 638-641.
29. Léran, S., Varala, K., Boyer, J.C., Chiurazzi, M., Crawford, N., Daniel-Vedèle, F., David, L., Dickstein, R., Fernandez, E., Forde, B., Gassmann, W., Geiger, D., Gojon, A., Gong, J.M., Halkier, B.A., Harris, J.M., Hedrich, R., Limami, A.M., Rentsch, D., Seo, M., Tsay, Y.F., Zhang, M., Coruzzi, G., Lacombe, B. (2014) A unified nomenclature of NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER family members in plants. Trends Plant Sci. 19: 5-9.
30. Seo, M. (2014) ABA transmembrane transport and transporters. in Absicisic acid: metabolism, transport and signaling. pp47-60. Ed Da-Peng Zhang. Springer.
31. 清水崇史、瀬尾光範 (2014) 輸送体研究における新たなアプローチ、植物の生長調節 49:74-80.
32. Yano, R., Takebayashi, Y., Nambara, E., Kamiya, Y., Seo, M. (2013) Combining association mapping and transcriptomics identify HD2B histone deacetylase as a genetic factor associated with seed dormancy in Arabidopsis thaliana. Plant J. 74: 815-828.
33. Jikumaru, Y., Seo, M., Matsuura H. and Kamiya, Y. (2013) Profiling of jasmonic acid-related metabolites and hormones in wounded leaves. Methods Mol. Biol. 1011: 113-122.
34. Kanno, Y., Kamiya, Y., Seo, M. (2013) Nitrate does not compete with abscisic acid as a substrate of AtNPF4.6/NRT1.2/AIT1 in Arabidopsis. Plant Signal. Behav. 8: e26624.
35. Liu, A., Gao, F., Kanno, Y., Jordan, M.C., Kmiya, Y., Seo, M., Ayele, B.T. (2013) Regulation of wheat seed dormancy by after-ripening is mediated by specific transcriptional switches that induce changes in seed hormone metabolisms and signaling. PLOS ONE 8: e56570.
36. Zarepour, M., Simon, K., Wilch, M., Nielander, U., Koshiba, T., Seo, M., Lindel, T., Bittner, F. (2012) Identification of superoxide production by Arabidopsis thaliana aldehyde oxidases AAO1 and AAO3. Plant Mol. Biol. 80: 659-671.
37. Nakabayashi, K., Bartsch, M., Xiang, Y., Miatton, E., Pellengahr, S., Yano, R., Seo, M., Soppe, W.J. (2012) The time required for dormancy release in Arabidopsis is determined by DELAY OF GERMINATION protein levels in freshly harvested seeds. Plant Cell 24: 2826-2838.
38. Kanno, Y., Hanada, A., Chiba, Y., Ichikawa, T., Nakazawa, M., Matsui, M., Koshiba, T., Kamiya, Y., Seo, M. (2012) Identidication of an abscisic acid transporter by functional screening using the receptor complex as a sensor. Proc. Natl. Acad. Sci. USA 109: 9653-9658.
39. Xu, Z.Y., Lee, K.H., Dongm, T, Jeong, C.J., Jin, J.B., Kanno, Y., Kim, D.H., Kim, S.Y., Seo, M., Bressan, R.A., Yun, D.J., Hwang, I. (2012) A novel vacuolar β-glucosidase homolog that possesses ABA-GE hydrolyzing activity plays an important role in osmotic stress responses in plants. Plant Cell 24: 2184-2199.
40. Frey, A., Effroy, D., Lefebbre, V., Seo, M., Perreau, F., Berger, A., Sechet, J., To, A., North, H., Marion-Poll, A. (2012) Epoxycarotenoid cleavage by NCED5 fine-tunes ABA accumulation and affects seed dormancy and drought tolerance with other NCED family members. Plant J. 70: 501-512.
41. Plackett, A.R.G., Powers, S., Fernandez-Garcia, N.M., Urbanova, T., Takebayashi, Y., Seo, M., Jikumaru, Y., Benlloch, R., Nilsson, O., Ruiz Rivero, O.J., Phillips, A.L., Wilson, Z.A., Thomas, S.G., Hedden, P. (2012) Analysis of the developmental roles of the Arabidopsis gibberellin 20-oxidases demonstrates that AtGA20ox1, -2 and -3 are the dominant paralogues. Plant Cell 24: 941-960
42. Seo, M. and Koshiba, T. (2011) Transport of ABA from the site of biosynthesis to the site of action. J. Plant Res. 124: 501-507.
43. Lackman, P., González-Guzmán, M., Tilleman, S., Carqueijeiro, I., Pérez, A.C., Moses, T., Seo, M., Kanno, Y., Häkkinen, S.T., Van Montagu, M.C., Thevelein, J.M., Maaheimo, H., Oksman-Caldentey, K.M., Rodriguez, P.L., Rischer, H., Goossens, A. (2011) Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco. Proc. Natl. Acad. Sci. USA 108: 5891-5896.
44. Seo, M., Jikumaru, Y. and Kamiya, Y. (2011) Profiling of hormones and related metabolites in seed dormancy and germination studies. Methods Mol. Biol. 773: 99-111.
45. Kanno, Y., Jikumaru, Y., Hanada, A., Nambara, E., Abrams, S.R., Kamiya, Y., Seo, M. (2010) Comprehensive hormone profiling in developing Arabidopsis seeds: examination of the site of ABA biosynthesis, ABA transport and hormone interactions. Plant Cell Physiol. 51: 1988-2001.
46. Seo, M., Nambara, E., Choi, G. and Yamaguchi, S. (2009) Interaction of light and hormone signals in germinating seeds. Plant Mol. Biol. 69: 463-472.
47. Ukaji, N., Kuwabara, C., Kanno, Y., Seo, M., Takezawa, D., Arakawa, K., Fujikawa, S. (2010) Endoplasmic reticulum-localized small heat-shock protein that accumulates in mulberry tree (Morus bombycis Koidz.) during seasonal cold acclimation is responsive to abscisic acid. Tree Physiol. 30: 502-513.
48. Ikegami, K., Okamoto, M., Seo, M., Koshiba, T. (2009) Activation of abscisic acid biosynthesis in the leaves of Arabidopsis thaliana in response to water deficit. J. Plant Res. 122: 235-43.