School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Korea.
Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 00826, Korea.
Mol Cells. 2021 Nov 30;44(11):830-842. doi: 10.14348/molcells.2021.0203.
When perceiving microbe-associated molecular patterns (MAMPs) or plant-derived damage-associated molecular patterns (DAMPs), plants alter their root growth and development by displaying a reduction in the root length and the formation of root hairs and lateral roots. The exogenous application of a MAMP peptide, flg22, was shown to affect root growth by suppressing meristem activity. In addition to MAMPs, the DAMP peptide PEP1 suppresses root growth while also promoting root hair formation. However, the question of whether and how these elicitor peptides affect the development of the vascular system in the root has not been explored. The cellular receptors of PEP1, and are highly expressed in the root vascular system, while the receptors of flg22 () and elf18 () are not. Consistent with the expression patterns of PEP1 receptors, we found that exogenously applied PEP1 has a strong impact on the division of stele cells, leading to a reduction of these cells. We also observed the alteration in the number and organization of cells that differentiate into xylem vessels. These PEP1-mediated developmental changes appear to be linked to the blockage of symplastic connections triggered by PEP1. PEP1 dramatically disrupts the symplastic movement of free green fluorescence protein (GFP) from phloem sieve elements to neighboring cells in the root meristem, leading to the deposition of a high level of callose between cells. Taken together, our first survey of PEP1-mediated vascular tissue development provides new insights into the PEP1 function as a regulator of cellular reprogramming in the Arabidopsis root vascular system.
当感知到微生物相关分子模式（MAMPs）或植物衍生的损伤相关分子模式（DAMPs）时，植物通过减少根长和根毛及侧根的形成来改变其根的生长和发育。外源应用 MAMP 肽 flg22 被证明通过抑制分生组织活性来影响根的生长。除了 MAMPs 之外，DAMP 肽 PEP1 抑制根的生长，同时促进根毛的形成。然而，这些激发子肽是否以及如何影响根中维管系统的发育尚未得到探索。PEP1 的细胞受体 和 在根维管系统中高度表达，而 flg22 的受体 () 和 elf18 的受体 () 则没有。与 PEP1 受体的表达模式一致，我们发现外源性施加的 PEP1 对中柱细胞的分裂有很强的影响，导致这些细胞减少。我们还观察到分化成木质部导管的细胞数量和组织的改变。这些 PEP1 介导的发育变化似乎与 PEP1 触发的质外体连接的阻断有关。PEP1 显著破坏了从韧皮部筛管到根分生组织邻近细胞的 free GFP 的共质体运动，导致细胞间高水平的胼胝质沉积。总之，我们对 PEP1 介导的血管组织发育的首次调查提供了新的见解，表明 PEP1 作为拟南芥根维管系统细胞重编程的调节剂的功能。
