Root endodermis, the innermost cortical layer surrounding the root vasculature, serves as the foremost barrier to water, solutes, and nutrients taken up from soil. Endodermis barrier functionality is achieved via its hydrophobic coating of lignified Casparian strips and the suberin lamellae; nonetheless the regulatory mechanisms underlying endodermis suberization are still elusive. Here, we discovered that the Arabidopsis SUBERMAN (SUB) transcription factor controls the establishment of the root suberin lamellae. Transient expression of SUB in Nicotiana benthamiana leaves resulted in the induction of heterologous suberin genes, the accumulation of suberin-type monomers, and consequent deposition of suberin-like lamellae. We demonstrate that SUB exerts its regulatory roles by transactivating promoters of suberin genes. In Arabidopsis, SUB is expressed in patchy and continuous suberization root endodermal cells, and thus roots with higher or lower expression of SUB display altered suberin polymer deposition patterns and modified composition. While these changes did not interfere with Casparian strip formation they had a substantial effect on root uptake capacity, resulting in varied root and leaf ionomic phenotypes. Gene expression profiling revealed that SUB function impacts transcriptional networks associated with suberin, phenylpropanoids, lignin, and cuticular lipid biosynthesis, as well as root transport activities, hormone signalling, and cell wall modification. Our findings highlight SUB as a regulator of root endodermis suberization during normal development, and its characterization is thus a key step towards dissecting the molecular mechanisms partaking in root endodermal barrier functionalities.

中文翻译：

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SUBERMAN调节拟南芥根内胚层的发育干化。

根部内胚层是围绕根部脉管系统的最内层皮质，是水，溶质和从土壤吸收的养分的最主要屏障。内胚层屏障功能是通过其木质化的里海带和木栓层的疏水涂层实现的。然而，内胚层皮下化的调节机制仍然难以捉摸。在这里，我们发现拟南芥SUBERMAN（SUB）转录因子控制着根薄木片的建立。SUB在烟草本草叶片中的瞬时表达导致异源Suberin基因的诱导，Suberin型单体的积累以及随后Suberin样片的沉积。我们证明SUB通过激活suberin基因的启动子发挥其调节作用。在拟南芥中 SUB在斑驳和连续的干化根皮内细胞中表达，因此具有较高或较低SUB表达的根表现出改变的Suberin聚合物沉积模式和修饰的组成。尽管这些变化不影响里海带的形成，但它们对根吸收能力有实质性影响，导致根和叶的基因组表型不同。基因表达谱分析表明，SUB功能影响与Suberin，苯基丙烷，木质素和表皮脂质生物合成相关的转录网络，以及根转运活性，激素信号传导和细胞壁修饰。我们的研究结果突显出SUB在正常发育过程中是根部内胚层干化的调节剂，