INRA, UMR1318, Institut Jean-Pierre Bourgin, Versailles, France.
Development. 2012 Apr;139(7):1306-15. doi: 10.1242/dev.072629.
Vascular development is embedded into the developmental context of plant organ differentiation and can be divided into the consecutive phases of vascular patterning and differentiation of specific vascular cell types (phloem and xylem). To date, only very few genetic determinants of phloem development are known. Here, we identify OCTOPUS (OPS) as a potentiator of phloem differentiation. OPS is a polarly localised membrane-associated protein that is initially expressed in provascular cells, and upon vascular cell type specification becomes restricted to the phloem cell lineage. OPS mutants display a reduction of cotyledon vascular pattern complexity and discontinuous phloem differentiation, whereas OPS overexpressers show accelerated progress of cotyledon vascular patterning and phloem differentiation. We propose that OPS participates in vascular differentiation by interpreting longitudinal signals that lead to the transformation of vascular initials into differentiating protophloem cells.
血管发育嵌入到植物器官分化的发育背景中，可以分为血管模式形成和特定血管细胞类型（韧皮部和木质部）分化的连续阶段。迄今为止，仅知道极少数韧皮部发育的遗传决定因素。在这里，我们将 OCTOPUS（OPS）鉴定为韧皮部分化的增强子。OPS 是一种极性定位于膜相关的蛋白，最初在原血管细胞中表达，并且在血管细胞类型特化后，其限制在韧皮部细胞谱系中。OPS 突变体显示子叶脉序复杂性降低和不连续的韧皮部分化，而 OPS 过表达体显示子叶脉序模式形成和韧皮部分化的加速进展。我们提出，OPS 通过解释导致血管原始细胞转化为分化的原韧皮部细胞的纵向信号来参与血管分化。
