Systems biology of cambium differentiation in Arabidopsis thaliana L.

揭示多细胞生物的细胞命运决定原理是生物学研究的一个基本目标。找出单个细胞如何通过与其他细胞相互作用来接管特殊功能是具有挑战性的，需要对细胞间通信和细胞内基因网络的反应进行全面的研究。一个具有指导意义的例子是植物生长轴的径向生长，这一过程基于形成层的活动，形成层是一种双面干细胞生态位，在相反的方向上产生木质部和韧皮部组织。在这个项目中，我们将利用植物径向生长的独特特性，并确定决定形成层双面特征的调节因子。这将通过遵循假设驱动的系统生物学方法来完成，该方法集成和挖掘组学数据、数学建模和计算机预测的实验验证。作为形成层组织的独特读取器，我们将使用最近生成的拟南芥pPXY:CFP pSMXL5:YFP启动子报告线和互补启动子活性来可视化形成层的双面组织。高通量图像分析技术与数学建模将用于分析不同实验条件下的报告动态，预测在我们的理论研究中提供信息。此外，在功能启动子分析的支持下，对PXY和SMXL5调控启动子区域进行生物信息学分析，将确定这些高度特异性的原皮部和原木质部标记上游的关键调控因子。大规模数据分析将进一步促进监管机构的识别，他们的潜在目标和决定性激素信号通路的交叉对话。总的来说，我们设想结合最先进的实验和系统生物学工具将确定干细胞生态位调节和植物内外生物量积累的基本机制。

Revealing principles of cell fate determination in multicellular organisms is one fundamental goal in biological studies. Finding out how a single cell takes over special functions by interacting with other cells is challenging and requires comprehensive studies on cell-to-cell communication and the response of intracellular gene networks. An instructive example is radial growth of plant growth axes, a process which is based on the activity of the cambium, a bifacial stem cell niche generating both xylem and phloem tissues in opposite directions. In this project, we will leverage the unique properties of radial plant growth and identify regulators which determine the bifacial character of the cambium. This will be done by following a hypothesis-driven systems biology approach integrating and mining omics data, mathematical modelling and experimental verification of in silico predictions. As a unique readout for cambium organization we will use a recently generated Arabidopsis thaliana pPXY:CFP pSMXL5:YFP promoter reporter line with complementary promoter activities visualizing the bifacial organization of the cambium. High-throughput image analysis techniques together with mathematical modelling will be used to analyse reporter dynamics in distinct experimental conditions predicted to be informative in our theoretical studies. Moreover, bioinformatic analysis of PXY and SMXL5 regulatory promoter regions supported by functional promoter analysis will identify key regulators upstream of those highly specific protophloem and protoxylem markers. Large scale data analysis will furthermore foster the identification of regulators, their potential targets and cross-talks with decisive hormone signalling pathways. Collectively, we envisage that the combination of state-of-the-art experimental and systems biology tools will identify fundamental mechanisms of stem cell niche regulation and the accumulation of biomass in plants and beyond.