Vaddepalli Prasad, Herrmann Anja, Fulton Lynette, Oelschner Maxi, Hillmer Stefan, Stratil Thomas F, Fastner Astrid, Hammes Ulrich Z, Ott Thomas, Robinson David G, Schneitz Kay
Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany.
Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg 69120, Germany.
Development. 2014 Nov;141(21):4139-48. doi: 10.1242/dev.113878. Epub 2014 Sep 25.
Tissue morphogenesis in plants requires communication between cells, a process involving the trafficking of molecules through plasmodesmata (PD). PD conductivity is regulated by endogenous and exogenous signals. However, the underlying signaling mechanisms remain enigmatic. In Arabidopsis, signal transduction mediated by the receptor-like kinase STRUBBELIG (SUB) contributes to inter-cell layer signaling during tissue morphogenesis. Previous analysis has revealed that SUB acts non-cell-autonomously suggesting that SUB controls tissue morphogenesis by participating in the formation or propagation of a downstream mobile signal. A genetic screen identified QUIRKY (QKY), encoding a predicted membrane-anchored C2-domain protein, as a component of SUB signaling. Here, we provide further insight into the role of QKY in this process. We show that like SUB, QKY exhibits non-cell-autonomy when expressed in a tissue-specific manner and that non-autonomy of QKY extends across several cells. In addition, we report on localization studies indicating that QKY and SUB localize to PD but independently of each other. FRET-FLIM analysis suggests that SUB and QKY are in close contact at PD in vivo. We propose a model where SUB and QKY interact at PD to promote tissue morphogenesis, thereby linking RLK-dependent signal transduction and intercellular communication mediated by PD.
植物中的组织形态发生需要细胞间的通讯，这一过程涉及分子通过胞间连丝（PD）的运输。PD的传导性受内源性和外源性信号调控。然而，其潜在的信号传导机制仍不清楚。在拟南芥中，类受体激酶STRUBBELIG（SUB）介导的信号转导在组织形态发生过程中有助于细胞层间的信号传导。先前的分析表明，SUB的作用是非细胞自主性的，这表明SUB通过参与下游移动信号的形成或传播来控制组织形态发生。一项遗传筛选确定了编码预测的膜锚定C2结构域蛋白的QUIRKY（QKY）是SUB信号传导的一个组成部分。在此，我们进一步深入了解QKY在此过程中的作用。我们发现，与SUB一样，当以组织特异性方式表达时，QKY表现出非细胞自主性，并且QKY的非自主性延伸到几个细胞。此外，我们报告了定位研究结果，表明QKY和SUB定位于PD，但彼此独立。FRET-FLIM分析表明，SUB和QKY在体内的PD处紧密接触。我们提出了一个模型，其中SUB和QKY在PD处相互作用以促进组织形态发生，从而将RLK依赖的信号转导与PD介导的细胞间通讯联系起来。
