n nnnThe root cap has a central role in root growth, determiningthe growth trajectory and facilitating penetration into thesoil. Root cap cells have specialized functions and morphologies,and border cells are released into the rhizosphere by specificcell wall modifications. Here, we demonstrate that the cellularmaturation of root cap is redundantly regulated by three genes,SOMBRERO (SMB), BEARSKIN1 (BRN1), and BRN2, which are membersof the Class IIB NAC transcription factor family, together withthe VASCULAR NAC DOMAIN (VND) and NAC SECONDARY WALL THICKENINGPROMOTING FACTOR (NST) genes that regulate secondary cell wallsynthesis in specialized cell types. Lateral cap cells in smb-3mutants continue to divide and fail to detach from the root,phenotypes that are independent of FEZ upregulation in smb-3.In brn1-1 brn2-1 double mutants, columella cells fail to detach,while in triple mutants, cells fail to mature in all parts ofthe cap. This complex genetic redundancy involves differencesin expression, protein activity, and target specificity. Allthree genes have very similar overexpression phenotypes to theVND/NST genes, indicating that members of this family are largelyfunctionally equivalent. Our results suggest that Class IIBNAC proteins regulate cell maturation in cells that undergoterminal differentiation with strong cell wall modifications.展开▼
机译：ABSTRACTn n
n TOP n <字体颜色= 464c53>抽象 n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n n nnn根冠在根的生长中起着核心作用，决定 的增长轨迹并有助于渗透到 土壤中。根冠细胞具有特殊的功能和形态， 和边界细胞通过特定的 细胞壁修饰释放到根际。在这里，我们证明根盖的细胞 的成熟度受三个基因 SOMBRERO （ SMB ）的冗余调控。 ， BEARSKIN1 （ BRN1 ）和 BRN2 ，它们是IIB NAC类转录因子家族的成员血管NAC域（ VND ）和 NAC二次墙增厚 促进因素 （ NST ）基因调节特定细胞类型中次级细胞壁 的合成。 smb-3 突变体中的侧向帽细胞继续分裂并且无法与根脱离， 表型与 FEZ < / I> smb-3 中的上调。 在 brn1-1 brn2-1 双重突变体中，小柱状细胞无法分离， < / SUP>，而在三重突变体中， 帽的所有部分中的细胞均无法成熟。这种复杂的遗传冗余涉及表达，蛋白质活性和靶标特异性方面的差异 。所有 三个基因的过表达表型与 VND / NST 基因非常相似，表明该家族成员是 在功能上大致相同。我们的研究结果表明，IIB NAC蛋白调节具有 末端分化并具有强烈细胞壁修饰的细胞的细胞成熟。展开▼
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands;
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands;
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands|Theoretical Biology and Bioinformatics, University of Utrecht, and Netherlands Consortium for Systems Biology, 3584 CH Utrecht, The Netherlands;
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands;
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands;
Theoretical Biology and Bioinformatics, University of Utrecht, and Netherlands Consortium for Systems Biology, 3584 CH Utrecht, The Netherlands;
Department of Molecular Genetics, University of Utrecht, 3584 CH Utrecht, The Netherlands;
