溫度依賴性生長有助於植物適應寒冷
作者:
小柯機器人發布時間:2020/7/16 16:52:27
英國約翰英納斯中心Martin Howard和Caroline Dean小組合作在研究中取得進展。他們的最新研究揭示溫度依賴性生長有助於植物長期對寒冷的感知。這一研究成果於2020年7月15日在線發表在國際學術期刊《自然》上。
通過正向遺傳篩選,研究人員發現了轉錄因子NTL8的兩個顯性突變,它們組成型激活了VERNALIZATION INSENSITIVE 3(VIN3)的表達並改變了VIN3的冷誘導曲線。在野生型植物中,NTL8蛋白在寒冷中緩慢積累,並直接上調VIN3轉錄。通過計算仿真和實驗驗證相結合的方法,研究人員證明這種緩慢累積的主要是由於在低溫下條件下植物緩慢生長導致NTL8稀釋度降低造成的。因此,通過蛋白質稀釋來利用溫度依賴性生長為VIN3上調提供了長期的熱感信息。除直接熱感外,在自然波動溫度的長期感知中與溫度依賴性生長有關的間接機制也可能參與其中。
據了解,溫度是影響所有生物生長和發育的關鍵因素。植物必須感知每小時至每月時間範圍內的溫度波動,以使其生長和發育適應季節。關於植物如何應對急性熱脅迫的研究很多,但是植物適應長期溫度變化的機制仍然未知。VIN3是一種PHD蛋白,它在冬季緩慢上調,在春化過程中與多梳抑制複合物一起在表觀遺傳上沉默開花抑制基因(FLC),這對理解植物冬季進程至關重要。
附:英文原文
Title: Temperature-dependent growth contributes to long-term cold sensing
Author: Yusheng Zhao, Rea L. Antoniou-Kourounioti, Grant Calder, Caroline Dean, Martin Howard
Issue&Volume: 2020-07-15
Abstract: Temperature is a key factor in the growth and development of all organisms1,2. Plants have to interpret temperature fluctuations, over hourly to monthly timescales, to align their growth and development with the seasons. Much is known about how plants respond to acute thermal stresses3,4, but the mechanisms that integrate long-term temperature exposure remain unknown. The slow, winter-long upregulation of VERNALIZATION INSENSITIVE 3 (VIN3)5,6,7, a PHD protein that functions with Polycomb repressive complex 2 to epigenetically silence FLOWERING LOCUS C (FLC) during vernalization, is central to plants interpreting winter progression5,6,8,9,10,11. Here, by a forward genetic screen, we identify two dominant mutations of the transcription factor NTL8 that constitutively activate VIN3 expression and alter the slow VIN3 cold induction profile. In the wild type, the NTL8 protein accumulates slowly in the cold, and directly upregulates VIN3 transcription. Through combining computational simulation and experimental validation, we show that a major contributor to this slow accumulation is reduced NTL8 dilution due to slow growth at low temperatures. Temperature-dependent growth is thus exploited through protein dilution to provide the long-term thermosensory information for VIN3 upregulation. Indirect mechanisms involving temperature-dependent growth, in addition to direct thermosensing, may be widely relevant in long-term biological sensing of naturally fluctuating temperatures.
DOI: 10.1038/s41586-020-2485-4
Source: https://www.nature.com/articles/s41586-020-2485-4