Functional characterisation of COR27 and COR28, two novel cold-induced phytochrome- and COP1/SPA binding proteins

光和温度是决定植物生长发育的重要环境因子。参与光形态建成和开花诱导的正调控的几个转录因子是COP 1/SPA E3泛素连接酶的靶点。COP 1/SPA复合物的活性被光激活的光敏色素和隐花色素下调，最近的报道表明COP 1也受温度控制。我们最近发现了两个新的光敏色素相互作用蛋白，COR 27和COR 28。COR 27和COR 28的表达强烈增强冷和转录组学数据表明，它们可能是由自主途径基因，HOS 1，和MYB/bHLH/WDR复合体，这是参与控制开花，冷反应，花青素的生物合成，分别调节。COR 27和COR 28与COP 1/SPA相互作用，但似乎不是其E3泛素连接酶活性的靶点，这表明它们可能调节COP 1/SPA复合物响应于光和温度的活性。因此，COR 27和COR 28可能有助于光和温度信号的整合，这对于生长和发育适应复杂和快速变化的环境是重要的。cor 27 cor 28双突变体开花较晚，并且过表达COR 27或COR 28的幼苗积累增加的花青素苷水平。本研究拟探讨COR 27和COR 28参与光温调控的分子机制，并研究COR 27和COR 28如何与COP 1/SPA和光敏色素整合光温信号，调控植物开花、花青素合成和冷反应。

Light and temperature are important environmental factors that determine plant growth and development. Several transcription factors involved in positive regulation of photomorphogenesis and induction of flowering are targets of the COP1/SPA E3 ubiquitin ligase. The activity of the COP1/SPA complex is downregulated by light-activated phytochromes and cryptochromes and recent reports show that COP1 is also controlled by temperature. We recently identified two novel phytochrome interacting proteins, COR27 and COR28. Expression of COR27 and COR28 is strongly enhanced by cold and transcriptomic data suggest that they might be regulated by autonomous pathway genes, HOS1, and the MYB/bHLH/WDR complex, which are involved in control of flowering, cold responses, and anthocyanin biosynthesis, respectively. COR27 and COR28 interact with COP1/SPA but appear not to be targets for their E3 ubiquitin ligase activity, suggesting instead that they might regulate the activity of the COP1/SPA complex in response to light and temperature. Thereby, COR27 and COR28 might contribute to light and temperature signal integration, which is important for the adaptation of growth and development to complex and rapidly changing environments. The cor27 cor28 double mutant is late flowering and seedlings overexpressing COR27 or COR28 accumulate increased levels of anthocyanin. In the proposed project we want to explore the molecular mechanisms involved in light and temperature regulation of COR27 and COR28, and investigate, how COR27 and COR28 together with COP1/SPA and phytochromes integrate light and temperature signals to regulate flowering, anthocyanin biosynthesis and cold responses.