植物の組織形成を規定するリン酸とピロリン酸の濃度バランス

• Project Area: Multidimensional Exploration of Logics of Plant Development
• Project/Area Number: 16H01235
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: Nagoya University
• Principal Investigator: 前島 正義 名古屋大学, 生命農学研究科, 教授 (80181577)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥10,140,000 (Direct Cost: ¥7,800,000、Indirect Cost: ¥2,340,000); Fiscal Year 2017: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2016: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
• Keywords: ピロリン酸 / 代謝調節 / 細胞壁 / ピロホスファターゼ / 窒素栄養 / 形態形成 / H+-PPase / プロトンポンプ / 液胞膜 / シロイヌナズナ / 器官形成 / 生体高分子合成

Outline of Annual Research Achievements

ピロリン酸（PPi）は核酸、タンパク質、多糖の生合成、脂肪の代謝の過程で生ずる代謝副産物であり、PPiを反応系から除去できなければ、これらの高分子合成は抑制される。一方、植物にはPPiを利用する酵素も存在し、PPi濃度の過度な低下も生育に負の影響を与える。細胞質PPiを無機リンに加水分解する酵素として、液胞膜H+輸送性ピロホスファターゼ（V-PPase）と可溶性ピロホスファターゼ（sPPase）が存在する。本研究は、これらの酵素がPPi濃度を適切に維持する機構を明らかにし、単純な無機化合物による形態形成制御という現象を深く理解することを目的とした。
二重破壊株V-PPaseとsPPaseは、低張液で根端が破裂するが、根端でセルロース量が大幅に減少していることを組織染色により実証した。細胞壁成分の化学分析においてもグルカンの低下を検出した。
V-PPase欠失株では培地窒素源にアンモニアが含まれない場合、本葉の萎縮という表現型が出現する。組織の萎縮はPPiの蓄積による細胞壁とクチクラ層の弱体化が原因と考えられる。また、アンモニアのほかに、アルギニンの培地添加も萎縮を顕著に抑制することを見出した。硝酸は地上部、アンモニアは根で主に同化されることから、硝酸限定条件では窒素代謝で生成するPPiが地上部に集中するため、V-PPase欠失株ではPPi加水分解能力を超えてしまうと推定した。
V-PPase発現量の極端に低い根端コルメラ細胞において、V-PPaseを異所発現させるとデンプン量の減少が見られたが、逆に発現量の極端に高い蜜腺では、開花に伴いV-PPaseとsPPaseが増加すること、遺伝子破壊株において蜜成分の量が減少することを発見した。V-PPaseとsPPaseが組織毎にPPiレベルを調節することでそれぞれ最適な糖の流れを決定していると考えられる。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] オックスフォード大学(英国)
• [Int'l Joint Research] ハイデルベルグ大学(ドイツ)
• [Int'l Joint Research] ハイデルベルグ大学(ドイツ)
• [Journal Article] Biochemical, structural, and physiological characteristics of vacuolar H(+)-pyrophosphatase. (2018)
  • Author(s): Segami, S., Asaoka, M., Kinoshita, S., Fukuda, M., Nakanishi, Y., and Maeshima, M.
  • Journal Title: Plant & Cell Physiology Volume: 59 Pages: 1300-1308
  • DOI: 10.1093/pcp/pcy054
  • NAID: 120006529619
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Vacuolar H(+)-pyrophosphatase and cytosolic soluble pyrophosphatases cooperatively regulate pyrophosphate levels in Arabidopsis thaliana. (2018)
  • Author(s): Segami, S., Tomoyama, T., Sakamoto, S., Gunji, S., Fukuda, M., Kinoshita, S., Mitsuda, N., Ferjani, A., and Maeshima, M.
  • Journal Title: The Plant Cell Volume: 30 Issue: 5 Pages: 1040-1061
  • DOI: 10.1105/tpc.17.00911
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Functionally redundant LNG3 and LNG4 genes regulate turgor-driven polar cell elongation through activation of XTH17 and XTH24 (2018)
  • Author(s): Lee, Y.K., Rhee, J., Lee, S.H., Chung, G.C., Park, S.J., Segami, S., Maeshima, M., and Choi, G.
  • Journal Title: Plant Molecular Biology Volume: In press Issue: 1-2 Pages: 23-36
  • DOI: 10.1007/s11103-018-0722-0
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Compensated cell enlargement in fugu5 is specifically triggered by lowered sucrose production from seed storage lipids. (2017)
  • Author(s): Takahashi, K., Morimoto, R., Ishida, M., Asaoka, M., Maeshima, M., Tsukaya, H., and Ferjani, A.
  • Journal Title: Plant & Cell Physiology Volume: 58 Issue: 4 Pages: 668-678
  • DOI: 10.1093/pcp/pcx021
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] SRPP, a cell-wall protein is involved in development and protection of seeds and root hairs in Arabidopsis thaliana (2017)
  • Author(s): Natsuki Tanaka, Hiroshi Uno, Shohei Okuda, Shizuka Gunji, Ali Ferjani, Takashi Aoyama, Masayoshi Maeshima
  • Journal Title: Plant Cell Physiology Volume: 58 Pages: 760-769
  • DOI: 10.1093/pcp/pcx008
  • NAID: 120006343667
  • Peer Reviewed
• [Journal Article] Enhancement of cell wall protein SRPP expression during emergent root hair development in Arabidopsis. (2017)
  • Author(s): Uno, H., Tanaka-Takada, N., Sato, R., and Maeshima, M.
  • Journal Title: Plant Signaling & Behavior Volume: 12 Issue: 10 Pages: e1368940-e1368940
  • DOI: 10.1080/15592324.2017.1368940
  • Peer Reviewed
• [Journal Article] A novel-type phosphatidylinositol phosphate-interactive, Ca-binding protein PCaP1 in Arabidopsis thaliana: stable association with plasma membrane and partial involvement in stomata closure. (2016)
  • Author(s): Nagata, C., Miwa, C., Tanaka, N., Kato, M., Suito, M., Tsuchihira, A., Sato, Y., Segami, S. and Maeshima, M.
  • Journal Title: Journal of Plant Research Volume: In press Issue: 3 Pages: 539-550
  • DOI: 10.1007/s10265-016-0787-2
  • NAID: 120005868252
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Contribution of PPi-hydrolyzing function of vacuolar H+-pyrophosphatase in vegetative growth of Arabidopsis: Evidenced by expression of uncoupling mutated enzymes. (2016)
  • Author(s): Asaoka, M., Segami, S., Ferjani, A., and Maeshima, M.
  • Journal Title: Frontiers in Plant Research Volume: 7 Pages: 415-415
  • DOI: 10.3389/fpls.2016.00415
  • NAID: 120005868253
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Lack of H+-pyrophosphatase causes developmental damage in Arabidopsis leaves in ammonia-free culture medium. (2016)
  • Author(s): Fukuda, M., Segami, S., Tomoyama, T., Nakanishi, Y., Gunji, S., Ferjani, A., and Maeshima, M.
  • Journal Title: Frontiers of Plant Science Volume: 6 Pages: 819-819
  • DOI: 10.3389/fpls.2016.00819
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Multiple facets of H+-pyrophosphatase and related enzymes. (2016)
  • Author(s): Ferjani, A., and Maeshima, M.
  • Journal Title: Frontiers of Plant Science Volume: 8
  • DOI: 10.3389/fpls.2016.01265
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Physiological Importance of Pyrophosphatases in Lateral Nectary of Arabidopsis thaliana. (2018)
  • Author(s): Kinoshita, S., Segami, S., and Maeshima, M.
  • Organizer: Japanese Society of Plant Physiologists
• [Presentation] 植物生体膜の物質輸送・情報変換システムに関わる生化学的・分子生理学的研究 (2018)
  • Author(s): 前島正義
  • Organizer: 日本植物生理学会
  • Invited
• [Presentation] Arabidopsis PCaP2 modulates the phosphatidylinositol 4,5-bisphosphate signal on the plasma membrane to attenuates root hair elongation. (2018)
  • Author(s): Kato, M., Tsuge, T., Maeshima, M., and Aoyama, T.
  • Organizer: Japanese Society of Plant Physiologists
• [Presentation] 植物の成長最適化に関わる代謝産物ピロリン酸濃度の調節. (2016)
  • Author(s): 前島正義、瀬上紹嗣、浅岡真理子、福田茉由、郡司 玄、Ali Ferjani
  • Organizer: 日本植物学会（シンポジウム）
  • Int'l Joint Research / Invited
• [Presentation] Dual functions of vacuolar H+-pyrophosphatase: vacuolar acidification and PPi homeostasis. (2016)
  • Author(s): Maeshima, M., Segami, S., Fukuda, M., Asaoka, M., Ferjani, A.
  • Organizer: 17th International Workshop on Plant Membrane Biology
  • Int'l Joint Research
• [Presentation] Dynamics of vacuoles and H+-pyrophosphatase visualized by monomeric green fluorescent protein in Arabidopsis. (2016)
  • Author(s): Segami, S. and Maesima, M.
  • Organizer: 17th International Workshop on Plant Membrane Biology
  • Int'l Joint Research
• [Presentation] Lack of H+-pyrophosphatase prompts developmental damage in Arabidopsis leaves on ammonia-free culture medium. (2016)
  • Author(s): Fukuda, M., Segami, S., Asaoka, M., Gunji, S., Ferjani, A., and Maeshima, M.
  • Organizer: 17th International Workshop on Plant Membrane Biology
  • Int'l Joint Research
• [Presentation] Molecular properties of proteins induced in root hairs under Pi deficiency. (2016)
  • Author(s): Tanaka, N., Kato, M., Fukao, Y., Aoyama, T., and Maeshima, M.
  • Organizer: 17th International Workshop on Plant Membrane Biology
  • Int'l Joint Research
• [Remarks] 名古屋大学生命農学研究科細胞ダイナミクス研究室
  • URL: http://celld.agr.nagoya-u.ac.jp/index.html