Abstract：
Inter-tissue communication is instrumental to coordinating the whole-body level behaviour for complex multicellular organisms. However, little is known about the regulation of inter-tissue information exchange. Here we carried out genetic screens for root-to-shoot mobile silencing in Arabidopsis plants with a compromised small RNA-mediated gene silencing movement rate and identified radical-induced cell death 1 (RCD1) as a critical regulator of root-shoot communication. RCD1 belongs to a family of poly (ADP-ribose) polymerase proteins, which are highly conserved across land plants. We found that RCD1 coordinates symplastic and apoplastic movement by modulating the sterol level of lipid rafts. The higher superoxide production in rcd1-knockout plants resulted in lower plasmodesmata (PD) frequency and altered PD structure in the symplasm of the hypocotyl cortex. Furthermore, the mutants showed increased lateral area of tracheary pits, which reduced axial movement. Our study highlights a novel mechanism through which root-to-shoot long-distance signalling can be modulated both symplastically and apoplastically.
摘要：
组织间通信有助于协调复杂多细胞生物的全身水平行为。然而,对组织间信息交换的调节知之甚少。在这里，我们对拟南芥植物中的根-芽移动沉默进行了遗传筛选，其中小RNA介导的基因沉默移动速率受损，并确定了自由基诱导的细胞死亡1（RCD1）作为根-芽通讯的关键调节因子。RCD1属于聚（ADP-核糖）聚合酶蛋白家族，在陆地植物中高度保守。我们发现RCD1通过调节脂筏的固醇水平来协调共生和质外生运动。rcd1敲除植物中超氧化物的产生较高，导致下胚轴皮质共生中的胞浆（PD）频率降低和PD结构改变。此外，突变体显示出外侧面积增加的气管坑，这减少了轴向运动。我们的研究强调了一种新的机制，通过该机制可以对根到芽的长距离信号进行对称和外生调制。
