Identification of ambient temperature responsive genes in rice under fluctuating natural conditions

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H03948
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 39:Agricultural and environmental biology and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: IZAWA TAKESHI 東京大学, 大学院農学生命科学研究科(農学部), 教授 (10263443)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: イネ / 光周性 / 花芽形成 / 気温応答性 / 自然環境 / 短日植物

Outline of Final Research Achievements

Here, we first examined flowering time under four distinct conditions: short-day or long-day and high or low temperature, using various rice lines. We also examined gene expression patterns of key flowering-time genes using the same lines under various conditions including temporal dynamics after light pulses. In addition to delayed flowering because of low growth rates, we found that photoperiodic flowering is clearly enhanced by both Hd1 and Ghd7 genes under low-temperature conditions in rice. We also revealed that PhyB can post-transcriptionally control Ghd7 repressor activity as a temperature sensor to inhibit Ehd1, Hd3a, and RFT1 at lower temperatures, despite inductive photoperiod conditions.The rising of ambient temperatures in early summer would contribute to inhibition of Ghd7 repressor activity, resulting in the appropriate floral induction of rice in temperate climates.

Free Research Field

植物分子遺伝学

Academic Significance and Societal Importance of the Research Achievements

モデル植物シロイヌナズナにおいて、光受容体フィトクロムが気温センサーとして働くことは報告があるが、今回の発見のように、特定の花芽形成制御遺伝子に関して、光受容体としては、転写制御、気温センサーとしては、活性制御というシステムの報告は新奇な発見となる。また、長日と低温が、フロリゲンの転写を強力に制限している事実は、作物としてのイネの育種において、重要な知見を提供する。