Systems biology of cambium differentiation in Arabidopsis thaliana L.

揭示多细胞生物体中细胞命运决定的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，需要对细胞间通讯和细胞内基因网络的反应进行全面研究。一个有指导意义的例子是植物生长轴的径向生长，这是一个基于形成层活动的过程，形成层是一个在相反方向上产生木质部和韧皮部组织的双面干细胞生态位。在这个项目中，我们将利用辐射状植物生长的独特特性，并确定决定形成层双面特征的调节剂。这将通过以下假设驱动的系统生物学方法来完成，该方法整合和挖掘组学数据，数学建模和实验验证计算机预测。作为形成层组织的独特读出，我们将使用最近产生的拟南芥pPXY：CFP pSMXL5：YFP启动子报告基因系，其具有互补启动子活性，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一起将被用来分析报告动力学在不同的实验条件下，预测在我们的理论研究是翔实的。此外，由功能性启动子分析支持的PXY和SMXL5调节启动子区域的生物信息学分析将鉴定那些高度特异性原生韧皮部和原生木质部标记物上游的关键调节子。大规模数据分析将进一步促进监管机构的识别，其潜在目标和与决定性激素信号通路的交叉对话。总的来说，我们设想，最先进的实验和系统生物学工具的结合将确定干细胞生态位调节和植物及其他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.