Analysisis of a novel gibberellin signaling pathway through calcium

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H04392
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Plant molecular biology/Plant physiology
• Research Institution: Hiroshima University
• Principal Investigator: Takahashi Yohsuke 広島大学, 理学研究科, 教授 (90183855)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 植物ホルモン / 信号伝達 / 転写制御

Outline of Final Research Achievements

DELLA proteins play a central role in gibberellin (GA) signaling. GA triggers DELLA degradation via the ubiquitin-proteasome pathway, thereby promoting plant growth. An increase in cytosolic Ca2+ was observed previously after several hours of GA application. Recent studies also suggest the existence of a DELLA-independent GA response. However, the effect of DELLA on the GA-induced increase in Ca2+ remains unknown. This study reexamined the effects of GAs on Ca2+ using the Ca2+ sensor protein in Arabidopsis. Ca2+ increased within a few minutes of GA treatment, even in transgenic plants expressing a mutated degradation-resistant version of DELLA and in della pentuple mutant plants. In addition, it was also revealed that Ca2+ is not involved in DELLA degradation. These results suggest that the GA-induced increase in Ca2+　occurs via a DELLA-independent pathway, providing important information on the GA signaling network.

Free Research Field

植物分子生物学

Academic Significance and Societal Importance of the Research Achievements

ジベレリン（GA）は植物の成長に顕著な促進作用を示すホルモンである。GAがいかにして植物の成長を制御しているのかを解明するためにGAの細胞内信号伝達に関する研究を行った。GA信号伝達において中心的な役割を果たしていると考えられているのが、DELLAタンパク質である。GAにより細胞内Ca2+濃度の上昇が速やかに誘導され、この誘導にはDELLAは関与しない事を明らかにした。本研究で見いだされたDELLAを介さないGA特異的な Ca2+濃度の上昇は未知のGA信号伝達経路の存在を示唆している。