Single-cell sequencing has recently allowed the generation of exhaustive root cell atlases. However, some cell types are elusive and remain underrepresented. Here we use a second-generation single-cell approach, where we zoom in on the root transcriptome sorting with specific markers to profile the phloem poles at an unprecedented resolution. Our data highlight the similarities among the developmental trajectories and gene regulatory networks common to protophloem sieve element (PSE)-adjacent lineages in relation to PSE enucleation, a key event in phloem biology. As a signature for early PSE-adjacent lineages, we have identified a set of DNA-binding with one finger (DOF) transcription factors, the PINEAPPLEs (PAPL), that act downstream of PHLOEM EARLY DOF (PEAR) genes and are important to guarantee a proper root nutrition in the transition to autotrophy. Our data provide a holistic view of the phloem poles that act as a functional unit in root development.

单细胞测序最近允许生成详尽的根细胞图谱。然而，一些细胞类型难以捉摸并且仍然未被充分代表。在这里，我们使用第二代单细胞方法，我们使用特定标记放大根转录组分类，以前所未有的分辨率分析韧皮部两极。我们的数据强调了与 PSE 去核相关的原生韧皮部筛元件 (PSE) 常见的发育轨迹和基因调控网络之间的相似性，PSE 去核是韧皮部生物学中的一个关键事件。作为早期 PSE 相邻谱系的标志，我们已经确定了一组 DNA 结合单指 (DOF) 转录因子，即菠萝 (PAPL)，它们作用于韧皮部早期DOF ( PEAR) 基因，并且对于保证在向自养过渡过程中适当的根系营养很重要。我们的数据提供了作为根系发育功能单元的韧皮部极的整体视图。