Deciphering the role of translation in temperature-controlled development

环境温度对植物发育的几乎所有方面都有深远的影响，从种子萌发和幼苗建立到花和果实的产生。因此，温度也强烈影响作物质量和产量。随着气候变化的进展，温带地区的植物受到更频繁的热浪以及环境温度整体上升的挑战。因此，深入了解植物对温度的反应对于充分了解气候变化如何影响植物未来的生长和发育至关重要，也可能表明如何减轻温度上升对作物生产的负面影响。我们最近使用核糖体分析（Ribo-seq）在全球范围内量化温暖的温度对模式植物拟南芥翻译动力学的影响。这使我们能够识别在较温暖的温度下进行增强翻译的转录本，例如编码植物温度信号传导中的关键参与者的PIF 7转录本。此外，这种方法还允许我们识别转录本的主要开放阅读框（ORF）上游进行翻译的序列。这种上游开放阅读框架（uORF）最近在许多生物系统中引起了关注。虽然它们的确切机制仍然知之甚少，但uORF通常被发现作为主要ORF翻译的控制元件。在植物中，已经在24-30%的转录物中发现了uORF，但是仅鉴定了其中少数的功能，其与控制形态发生、代谢和抗病性有关。在我们的Ribo-seq数据中，我们鉴定了多个拟南芥uORF，其翻译以温度依赖性方式变化。该项目将采用遗传和分子生物学方法来揭示几个候选uORF在植物发育和非生物胁迫响应中的功能，特别强调温度敏感性过程。它还将使用体外和体内生化测定来解决这些uORF是否以及如何影响基因功能的问题。这些以候选基因为中心的方法将得到全转录组翻译起始分析的补充，旨在揭示uORF翻译在一系列环境温度下的精确动态。总之，这些方法将提供一个详细的温度调节的uORF景观，并揭示温度敏感的uORF在拟南芥中的新功能。

Ambient temperature has profound effects on almost all aspects of plant development, from the onset of seed germination and seedling establishment to flower and fruit production. Consequently, temperature also strongly impacts crop quality and yield. With the progression of climate change, plants in temperate regions are challenged by more frequent heat waves as well as an overall rise in ambient temperature. Gaining insight into a plant's response to temperature is thus vital to fully understand how climate change will affect plant growth and development in the future and may also indicate ways to mitigate negative effects of rising temperatures on crop production. We recently used Ribosome Profiling (Ribo-seq) to quantify the effect of warm temperature on translation dynamics in the model plant Arabidopsis thaliana at a global level. This allowed us to identify transcripts that undergo enhanced translation at warmer temperature, for instance the PIF7 transcript that encodes a key player in plant temperature signalling. In addition, this approach also allowed us to identify sequences upstream of a transcript's main open reading frame (ORF) that undergo translation. Such upstream open reading frames (uORFs) have recently attracted attention in many biological systems. While their precise mechanism still remains poorly understood, uORFs were often found to act as control elements for translation of the main ORF. In plants, uORFs have been found in 24-30% of transcripts, but a function has only been identified for few of them, linked to the control of morphogenesis, metabolism and disease resistance. In our Ribo-seq data, we identified multiple Arabidopsis uORFs whose translation changes in a temperature-dependent manner. This project will employ genetic and molecular biology approaches to reveal the functions of several candidate uORFs in plant development and abiotic stress responses, with a particular emphasis on temperature-sensitive processes. It will also tackle the question whether and how these uORFs affect gene function, using in vitro and in vivo biochemical assays. These candidate gene-focused approaches will be complemented by transcriptome-wide analysis of translation initiation, aiming to reveal precise dynamics of uORF translation across a range of ambient temperatures. Together, these approaches will provide a detailed view of the temperature-regulated uORF landscape and reveal novel functions of temperature-sensitive uORFs in Arabidopsis.