Analysis of the mechanism of polarity establishment on the plasma membrane for polar secretion in Plants.

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H05068
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied molecular and cellular biology
• Research Institution: Kyoto Prefectural University
• Principal Investigator: Sato Masa H. 京都府立大学, 生命環境科学研究科, 教授 (20283575)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: ホスホイノシチド / 極性確率 / 膜交通 / 根毛形成 / シロイヌナズナ

Outline of Final Research Achievements

Root hairs elongate by tip growth and simultaneously harden the shank by constructing the inner secondary cell wall layer. Here we show that PI(3,5)P2, the enzymatic product of FAB1, is involved in the hardening of the shank in root hairs in Arabidopsis. FAB1 and PI(3,5)P2 localize to the plasma membrane along the shank of growing root hairs. By contrast phosphatidylinositol 4-phosphate 5-kinases 3 (PIP5K3) and PI(4,5)P2 localize to the apex of root hair where they are required for tip growth. Reduction of FAB1 function results in the formation of wavy root hairs while wild type are straight. The localization of FAB1 in the plasma membrane of root hair shank requires the activity of Rho-related GTPases from plants 10 (ROP10) and localization of ROP10 requires FAB1 activity. Computational modelling of root hair morphogenesis successfully reproduces the wavy root hair phenotype. Taken together, these data demonstrate that the root hair shank hardening requires PI(3,5)P2/ROP10 signaling.

Free Research Field

植物分子生物学，細胞生物学

Academic Significance and Societal Importance of the Research Achievements

本研究は，申請者が発見した二種類のイノシトールリン脂質の細胞膜上の偏在性に注目し，極性分泌制御の観点から植物細胞の形態形成の基本原理を明らかにしようとする挑戦的な研究である。植物にとっての極性分泌現象は，クチクラや根における金属キレート物質の分泌，蜜腺での蜜の分泌，ワックスの分泌などにも必須の現象である。今回明らかになったFAB１およびPI(3,5)P2による細胞の極性分泌メカニズムの理解は，応用的には，農作物や花きなどの形の制御による品種改良，細胞壁やクチクラ，ワックス層の増強による病害性抵抗性増強などにつながる基盤技術になると考えている。