Temperature is a key factor in the growth and development of all organisms 1 , 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 stresses 3 , 4 , but the mechanisms that integrate long-term temperature exposure remain unknown. The slow, winter-long upregulation of VERNALIZATION INSENSITIVE 3 (VIN3) 5 – 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 progression 5 , 6 , 8 – 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. The authors find that slow plant growth at low temperatures during winter reduces dilution of the transcription factor NTL8, which allows slow accumulation of NTL8 and thus the gradual increase in transcription of VIN3 —a gene involved in memory of cold exposure.

中文翻译：

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温度依赖性生长有助于长期冷传感

温度是所有生物体生长和发育的关键因素 1, 2 。植物必须解释每小时到每月的温度波动，以使它们的生长和发育与季节保持一致。人们对植物如何应对急性热应激 3 、 4 已经了解很多，但整合长期温度暴露的机制仍然未知。春化不敏感 3 (VIN3) 5 – 7 是一种 PHD 蛋白，它与 Polycomb 抑制复合物 2 一起发挥作用，在春化过程中表观遗传地沉默 FLOWERING LOCUS C ( FLC )，其在整个冬季缓慢上调，对于植物解释冬季进程至关重要 5 , 6 ， 8 – 11 。在这里，通过正向遗传筛选，我们鉴定了转录因子 NTL8 的两个显性突变，它们组成性激活 VIN3 表达并改变缓慢的 VIN3 冷诱导曲线。在野生型中，NTL8蛋白在寒冷中缓慢积累，并直接上调VIN3转录。通过结合计算模拟和实验验证，我们发现这种缓慢积累的主要原因是由于低温下生长缓慢而导致的 NTL8 稀释减少。因此，通过蛋白质稀释来利用温度依赖性生长，为 VIN3 上调提供长期热传感信息。除了直接热传感之外，涉及温度依赖性生长的间接机制可能与自然波动温度的长期生物传感广泛相关。作者发现，冬季低温下植物生长缓慢会减少转录因子 NTL8 的稀释，从而使 NT​​L8 缓慢积累，从而逐渐增加 VIN3（一种与寒冷暴露记忆有关的基因）的转录。