Scientific Breakthrough: Chinese Scientists Decode Rice's High-Temperature Perception Mechanism

全球氣候暖化對糧食安全構成嚴重威脅，亟需挖掘作物耐熱基因、解析其機制，以培育適應高溫的新品種。近日，中國科學院分子植物科學卓越創新中心林鴻宣院士團隊，攜手上海交通大學林尤舜研究員團隊及廣州國家實驗室李亦學研究員團隊，經多年研究，成功破解水稻感知與響應高溫的「雙重密碼」，並透過遺傳改良培育出具有「梯度耐熱性」的水稻新株系。該項重要研究成果已於12月3日發表於國際頂尖學術期刊《細胞》（Cell）。

Global warming poses a severe threat to food security, creating an urgent need to identify heat-tolerant genes in crops, understand their mechanisms, and develop new varieties adapted to high temperatures. Recently, a research team led by Academician Lin Hongxuan from the Center for Excellence in Molecular Plant Sciences of the Chinese Academy of Sciences, in collaboration with teams led by Researcher Lin Youshun from Shanghai Jiao Tong University and Researcher Li Yixue from Guangzhou National Laboratory, successfully deciphered the "dual codes" for rice to perceive and respond to high temperature after years of effort. They have also developed new rice lines with "gradient heat tolerance" through genetic improvement. This significant research was published in the prestigious international academic journal Cell on December 3.

據林鴻宣院士說明，第一重密碼位於細胞膜上的「脂質密碼」。當高溫信號抵達植物細胞的「邊境城牆」—細胞膜時，膜上的「哨兵」二酰甘油激酶（DGK7）首先被激活，解碼並啟動第一重信號響應，大量生成名為「磷脂酸（PA）」的脂質信使。此過程完成了高溫信號的首次轉換與放大，將外界物理高溫轉化為細胞內的化學警報。該機制具有自我調節功能，避免信號無限放大，以維持細胞內部穩態。

According to Academician Lin Hongxuan, the first layer is the "lipid code" on the cell membrane. When the high-temperature signal reaches the "border wall" of the plant cell—the cell membrane, the "sentry" on the membrane, diacylglycerol kinase 7 (DGK7), is first activated. It decodes and initiates the first layer of signal response, generating large amounts of a lipid messenger called phosphatidic acid (PA). This process accomplishes the initial conversion and amplification of the high-temperature signal, transforming external physical heat into a chemical alarm within the cell. This mechanism includes a regulatory constraint to prevent infinite amplification, thereby maintaining overall cellular homeostasis.

第二重密碼則是細胞核內的「環核苷酸密碼」。作為信使的「磷脂酸（PA）」進入細胞內部後，精準傳遞高溫信號，激活「中層指揮官」磷酸二酯酶（MdPDE1），並協助其進入「核心司令部」細胞核。MdPDE1透過降解另一種信使分子環核苷酸（cAMP），促使細胞合成各種「耐熱武器」，從常態轉入高溫應急狀態，從而抵禦高溫脅迫，表現出耐熱性。

The second layer is the "cyclic nucleotide code" within the nucleus. The messenger phosphatidic acid (PA) enters the cell interior, precisely relays the high-temperature signal, activates the "mid-level commander" phosphodiesterase MdPDE1, and facilitates its entry into the "core command center"—the nucleus. MdPDE1 promotes the synthesis of various "heat-resistance weapons" within the cell by degrading another messenger molecule, cyclic adenosine monophosphate (cAMP). This shifts the cell from a normal state to a high-temperature emergency response state, enabling it to withstand heat stress and exhibit a heat-tolerant phenotype.

林鴻宣院士表示：「DGK7和MdPDE1是我們成功鑑定的水稻細胞中兩個關鍵調控因子。它們如同一套精密協作的警報系統，將高溫物理信號逐步轉化為細胞能夠理解的生物指令，完成了一場從細胞邊界到細胞核的傳訊之旅。」

"DGK7 and MdPDE1 are two key regulatory factors we successfully identified in rice cells," said Academician Lin Hongxuan. "They function like a precisely coordinated alarm system, step by step converting the physical high-temperature signal into biological instructions that the cell can understand, thereby completing a relay of information from the cell boundary to the nucleus."

該研究不僅破解了領域內的長期難題，也為育種提供了精準靶點。基於「雙重密碼」進行遺傳設計，模擬高溫的田間試驗結果令人振奮：相較對照組，DGK7或MdPDE1單基因改良的水稻株系增產50%-60%；而耐熱基因TT2協同DGK7的雙基因改良株系，產量提升約一倍，米質更佳，且不影響正常條件下的產量。

This research not only solves a long-standing challenge in the field but also provides precise targets for breeding. Genetic design based on the "dual codes" yielded exciting results in simulated high-temperature field trials: compared to the control lines, rice lines改良ed with either the DGK7 or MdPDE1 single gene showed a 50%-60% increase in yield. Furthermore, lines改良ed with both the heat-tolerant gene TT2 and DGK7 demonstrated approximately double the yield, improved grain quality, without compromising yield under normal conditions.

這意味著，科學家現在不僅能增強作物的耐熱性，更能像調節音量般精準設計具有「梯度耐熱」特性的品種，以適應不同地區的氣候需求，維持高溫環境下的作物產量穩定。

This signifies that scientists can now not only enhance the heat tolerance of crops but also precisely design varieties with "gradient heat tolerance," akin to adjusting a volume dial, to meet the climatic needs of different regions and maintain stable crop yields under high-temperature environments.

業內專家認為，此項研究為水稻、小麥、玉米等主糧作物的耐熱育種改良，提供了堅實的理論框架與寶貴的基因資源，為在全球暖化背景下保障糧食安全開闢了新的路徑。

Industry experts believe this research provides a solid theoretical framework and valuable genetic resources for improving heat tolerance in staple crops such as rice, wheat, and maize, opening a new pathway to ensuring food security in the context of global warming.

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