StPCP1: an IDD transcription factor involved in sugar-induced flowering and tuberization in Solanum tuberosum

在马铃薯植物（Solanum tuberosum）中，开花和块茎形成都采用类似的诱导途径。由于马铃薯是为地下贮藏器官而栽培的，块茎形成的时间和块茎产量在粮食安全方面具有越来越重要的意义，这就是为什么块茎诱导因子和影响块茎品质性状的机制的鉴定在植物研究和农业中具有最广泛的兴趣。在这个建议中，我们建议的优先程序SPP 1530的框架内影响开花和块茎形成的途径的表征。开花和块茎形成是通过多因子途径调节的发育过程。我们特别感兴趣的是了解这些途径如何与植物中的一般代谢过程相结合。POTATO COUCH POTATO 1（StPCP 1）蛋白是IDD转录因子家族的转录因子。StPCP 1 RNAi植物表现出开花和块茎形成表型。初步的定量真实的时间PCR分析表明，StPCP 1是糖转运蛋白的一般调节剂，从而影响马铃薯植物中的碳水化合物状态。几个韧皮部移动的信号已被提出来报告源叶的蔗糖状态到库器官，如茎尖分生组织或匍匐茎尖。我们计划更详细地研究这些假定的韧皮部移动的因子，特别是海藻糖6-磷酸，miR 156和miR 172以及它们的靶点。初步研究表明，叶片中的蔗糖含量反映了这些信号成分的表达和合成的变化，正如拟南芥所示。我们进一步提出表征StPCP 1作为转录因子及其下游靶点的性质。这具体涉及蔗糖转运蛋白（例如StSUT 4）的直接调节和通过已知ID 1结构域的结合调节其他下游靶标。与此同时，我们将解决与已知的信号通路的相互作用，导致马铃薯开花和块茎形成，即光周期和T6 P途径，因为它们已被证明是受StPCP 1的影响。

In potato plants (Solanum tuberosum) both flowering and tuberization employ similar inducing pathways. Since potato is cultivated for its underground storage organs, the time to tuberization and the tuber yield is of growing significance in terms of food security, which is why the identification of tuber inducing factors and mechanisms also affecting tuber quality traits is of broadest interest in plant research and agriculture. In this proposal we suggest the characterization of pathways affecting flowering and tuberization in potato within the framework of the priority program SPP1530. Flowering and tuberization are developmental processes that are regulated via multifactorial pathways. We are especially interested in understanding how these pathways converge with general metabolic processes in the plant. The POTATO COUCH POTATO1 (StPCP1) protein is a transcription factor of the IDD transcription factor family. StPCP1 RNAi plants show a flowering and tuberization phenotype. Preliminary quantitative real time PCR analyses suggest that StPCP1 is a general regulator of sugar transporters thereby influencing the carbohydrate status in potato plants. Several phloem mobile signals have been suggested to report of the sucrose status of source leaves to sink organs such as the shoot apical meristem or the stolon tips. We plan on investigating these putative phloem mobile factors in more detail, in particular trehalose 6-phosphate, miR156 and miR172 as well as their targets. Preliminary studies indicate that the sucrose content in the leaves is reflected by a changed expression and syntheses of these signaling components, as it has been shown for Arabidopsis. We further propose characterizing the nature of StPCP1 as a transcription factor as well as its downstream targets. This specifically involves the direct regulation of sucrose transporters (e.g. StSUT4) and the regulation of further downstream targets via the binding of the known ID1 domain. At the same time we will address open questions regarding the interaction with known signaling pathways leading to flowering and tuberization in potato, i.e. the photoperiod and the T6P pathways, as they have been shown to be affected by StPCP1.