Analysis of the gibberellin/jasmonate transport mechanism by GTR1 during flower development

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K18552
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Plant molecular biology/Plant physiology
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Sasaki-Sekimoto Yuko (関本結子) 東京工業大学, 生命理工学院, 研究員 (60422557)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: ジャスモン酸 / ジベレリン

Outline of Final Research Achievements

Jasmonates (JAs) and gibberellins (GAs) have essential roles in regulating fertilization of Arabidopsis. We reported that GLUCOSINOLATE TRANSPORTER 1 (GTR1) expressed in Xenopus oocytes functions as a transporter for a bioactive form of JA and GA. We also show that gtr1 flowers have less bioactive GA, and the phenotype was complemented by the supplementation of bioactive GA, but not JA, suggesting GTR1 regulates fertility (Saito et al., 2015).
Here, we focused on the gene expression profiles, and found that gtr1 had some defect in normal GA biosynthesis and/or distribution in flowers. GTR2 is a close homolog of GTR1. We investigated phenotypes of gtr1, gtr2 and gtr1gtr2 double mutants, and found that gtr1gtr2 has shorter epidermal cells in filaments than that of WT. However, gtr1gtr2 had the same number of epidermal cells observed in WT. These results show that GTR1 and GTR2 have redundant functions in filament elongation, and such process is crucial to regulate timing of pollinizer.

Free Research Field

植物生理学

Academic Significance and Societal Importance of the Research Achievements

花粉の受粉のタイミングは植物ホルモンによって制御されている。本研究では花芽の発達時において植物ホルモンの１つジベレリンの輸送体として機能するGTR1およびその相同遺伝子GTR2の詳細な機能解析を行い、これらが花糸の伸長制御を介して受粉のタイミングを制御していることを示した。受粉が適切なタイミングで行われることは、作物の収量にも大きな影響を与える。そのため、受粉タイミングの制御機構の一端が明らかになることは、基礎研究のみならず、農業分野においても重要な知見となる。