Cellular dynamics and regulation of cambium stem cells during secondary growth

地球森林中的大部分植物生物量都是形成层的产物。作为植物茎中的一个圆柱形分生组织区域，形成层含有形成层干细胞(CSCs)，它为向内产生木质部和向外产生韧皮部提供细胞，从而沿放射轴扩大植物体内。这种次生加厚生长通过产生次生维管束在生理上支持植物的持续生长，在机械上通过扩大轴的半径来支持植物的持续生长。尽管它们很重要，但对CSC增殖和分化的调控机制仍然知之甚少。以拟南芥形成层为模型系统，试图揭示CSCs的调控机制，使其能够实现持续的二次生长。我将揭示CSCs在二次生长过程中的细胞动力学，并用单细胞分辨率表征CSCs及其分化的子代的转录组，以确定形成层中的新原理和调节因子。CSC系统不同于其他植物干细胞系统，如顶端分生组织细胞系统，其动力学和双面分化模式不同。我提出的工作不仅将加速CSC的研究，而且将为未来植物干细胞研究提供有价值的见解。

Most of the plant biomass in the Earth’s forests is the product of the cambium. As a cylindrical meristematic region in plant stems, the cambium harbours cambium stem cells (CSCs) that provide cells for generating xylem inwards and phloem outwards to enlarge the plant body along the radial axis. This secondary thickening growth supports the continuous growth of plants physiologically by generating secondary vasculature and mechanically by enlarging the radius of the axes. Despite their importance, the regulatory mechanisms of CSC proliferation and differentiation remain poorly understood. Using the Arabidopsis cambium as a model system, I propose to reveal the regulatory mechanisms of CSCs enabling the continuous secondary growth. I will uncover the cellular dynamics of CSCs during secondary growth and characterize the transcriptome of CSCs and their differentiating daughters with single-cell resolution to identify novel principles and regulators in the cambium. The CSC system differs from other plant stem cell systems like the apical meristem stem cell systems in its dynamics and in the bifacial differentiation pattern. My proposed work will not only accelerate CSC research, but will also provide valuable insights for the future studies of plant stem cell research.