Polarly localized receptor-like kinases PXC2 and IRK act redundantly during Arabidopsis root development in the radial axis
Polarly localized receptor-like kinases PXC2 and IRK act redundantly during Arabidopsis root development in the radial axis
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DOI：
10.1101/2021.02.11.429611
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发表时间：
2021-02
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影响因子：
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通讯作者：
Jason Goff;Jaimie M. van Norman
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作者：
Jason Goff;Jaimie M. van Norman
在植物中，细胞分裂和分化的协调对于组织形成和器官发育至关重要。定向细胞信号传导和细胞极性已被提出参与这些发育过程的协调。例如，一种名为开花和根尖激酶（IRK）的富含亮氨酸重复序列受体样激酶（LRR-RLK）的功能是限制中柱面积并抑制极性定位的内皮层中的纵向垂周分裂（LAD）。与IRK最密切相关的LRR-RLK是PXY/TDR相关2（PXC 2），我们发现PXC 2在根细胞类型中显示出与IRK相似的极化积累。为了进一步了解这些蛋白质如何在定向细胞-细胞信号传导和根发育中发挥作用，我们探索了PXC 2的功能。pxc 2根的中柱面积增加，表明PXC 2也具有限制中柱大小的功能。此外，与任一单一突变体相比，irk pxc 2根具有增强的表型，内胚层LAD和中柱面积进一步增加，表明这些受体的冗余活性。双突变体也表现出异常的根生长，表明更广泛的功能PXC 2和IRK在根中。然而，PXC 2在功能上并不等同于IRK，因为PXC 2的内胚层错误表达并不能完全拯救IRK。我们建议，PXC 2是至少部分冗余的IRK与更主要的作用，IRK在抑制内胚层LAD。我们的研究结果是一致的假设，即通过PXC 2/IRK介导的定向信号通路抑制特定的内胚层细胞分裂和中柱面积是协调根的生长和发育所必需的。在根中，生长和发育过程的协调是至关重要的器官功能和定向细胞间信号传导和细胞极性在这些过程中牵连。我们的研究表明，横向极性跨膜受体激酶，PXC 2和IRK，限制特定的内胚层细胞分裂和中柱大小的冗余功能，是重要的向地性根的生长。
In plants, coordination of cell division and differentiation is critical for tissue patterning and organ development. Directional cell signaling and cell polarity have been proposed to participate in coordination of these developmental processes. For instance, a leucine-rich repeat receptor-like kinase (LRR-RLK) named INFLORESCENCE AND ROOT APICES KINASE (IRK) functions to restrict stele area and inhibit longitudinal anticlinal divisions (LADs) in the endodermis where it is polarly localized. The LRR-RLK most closely related to IRK is PXY/TDR CORRELATED 2 (PXC2) and we find that PXC2 shows similar polarized accumulation as IRK in root cell types. To further understand how these proteins operate in directional cell-cell signaling and root development we explored PXC2 function. pxc2 roots have an increase in stele area, indicating that PXC2 also functions to restrict stele size. Additionally, compared to either single mutant, irk pxc2 roots have an enhanced phenotype with further increases in endodermal LADs and stele area indicating redundant activities of these receptors. The double mutant also exhibits abnormal root growth, suggesting broader functions of PXC2 and IRK in the root. However, PXC2 is not functionally equivalent to IRK, as endodermal misexpression of PXC2 did not fully rescue irk. We propose that PXC2 is at least partially redundant to IRK with a more predominant role for IRK in repression of endodermal LADs. Our results are consistent with the hypothesis that repression of specific endodermal cell divisions and stele area through a PXC2/IRK-mediated directional signaling pathway is required for coordinated root growth and development.In the root, coordination of growth and developmental processes is critical for organ function and directional cell-to-cell signaling and cell polarity are implicated in these processes. Our studies indicate that laterally polar transmembrane receptor kinases, PXC2 and IRK, have redundant functions in restriction of specific endodermal cell divisions and stele size, and are important for gravitropic root growth.