Control of Directionality of Plant Tip Growth by Microtubule-associated Proteins

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06726
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44030:Plant molecular biology and physiology-related
• Research Institution: Miyagi University
• Principal Investigator: Hiwatashi Yuji 宮城大学, 食産業学群, 教授 (10373193)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 先端成長 / 微小管 / 微小管関連因子 / オーグミン / キネシン / ヒメツリガネゴケ / スサビノリ / ライブイメージング

Outline of Final Research Achievements

The microtubule (MT) -associated proteins were analyzed in the tip-growing cells of the moss Physcomitrium patens to understand the molecular mechanisms underlying the directionality of growth. We found that MT-dependent MT generator (AUG8), MT-maintaining protein (PpAIR9), and MT-depolymerizing factor (UDL1) were involved in controlling the directionality of expansion in tip growth. The agravitropic mutants were isolated to identify the regulators for tip growth. Phenotypic and genetic analyses suggested that KCHb, a member of kinesin-14, functioned in determinating the direction of tip growth in response to gravity. We established a live-imaging technique to analyze the tip growth of conchocelis in the red alga N. yezoensis. The directionality and tip growth expansion were disrupted by the application of MT drugs, suggesting the involvement of MTs in these processes. The live-imaging analysis is a versatile approach for exploring the dynamics of tip growth in conchocelis.

Free Research Field

植物細胞生理学、植物分子遺伝学

Academic Significance and Societal Importance of the Research Achievements

微小管の生成、維持、消失因子がそれぞれ特異的な局在パターンで、ヒメツリガネゴケの先端成長の方向性制御に作用するメカニズムを解明したことは、微小管の組織化による先端成長制御の全体像を俯瞰的に理解できる点で学術的な意義がある。また、ヒメツリガネゴケのみならず、被子植物シロイヌナズナの相同因子の機能解析や紅藻スサビノリの先端成長解析により微小管を介した先端成長の方向性制御の進化的考察がなされた点は独創的である。スサビノリは海苔の原料で、その糸状体はノリ養殖時に使用されることから、成長制御の理解はノリ養殖技術の発展に寄与できる。