植物根发育与逆境发育生物学团队《Journal of Integrative Plant Biology》2022年
论文题目：TGA factors promote plant root growth by modulating redox homeostasis or response
论文作者：Xiaochen Hu,Liyun Yang,Mengfei Ren,Lin Liu,Jing Fu,Hongchang Cui
论文摘要：To identify novel regulators of stem cell renewal, we mined an existing but little explored cell-type-specific transcriptome dataset for the Arabidopsis root. A member of the TGA family of transcription factors, TGA8, was found to be specifically expressed in the quiescent center (QC). Mutation in TGA8 caused a subtle root growth phenotype, suggesting functional redundancy with other TGA members. Using a promoter::HGFP transgenic approach, we showed that all TGA factors were expressed in the root, albeit at different levels and with distinct spatial patterns. Mutant analyses revealed that all TGA factors examined contribute to root growth by promoting stem-cell renewal, meristem activity and cell elongation. Combining transcriptome analyses, histochemical assays and physiological tests, we demonstrated that functional redundancy exists among members of clades II and V or those in clades I and III. These two groups of TGA factors act differently, however, as their mutants responded to oxidative stress differently and qRT-PCR assays showed they regulate different sets of genes that are involved in redox homeostasis. Our study has thus uncovered a previously unrecognized broad role and a mechanistic explanation for TGA factors in root growth and development.
为了发现新的控制干细胞更新的调控因子，我们对一组现有但很少被利用的拟南芥根中不同细胞类型的转录组数据进行了挖掘，发现TGA家族的转录因子之一，TGA8，在静止中心(quiescent center, QC)特异表达。与野生型相比，TGA8突变体根长略微变短，说明TGA8有调控根生长的作用，但与其他TGA成员存在功能冗余。 利用启动子::HGFP转基因方法，我们发现所有TGA因子都在根中表达，尽管表达水平不同，且具有不同的细胞型特异性。 突变体分析表明，所有TGA因子均通过促进干细胞更新、分生组织活性和细胞伸长来促进根的生长。 结合转录组分析、组织化学分析和生理测试，我们证明了在进化支II和V或进化支I和III的成员之间存在功能冗余。 然而，这两组TGA因子的作用不同，因为它们的突变体对过氧化氢应激的反应不同。qRT-PCR分析显示，它们可能通过调节不同的参与氧化还原稳态的基因影响细胞氧化还原稳态。 综上所述，我们的研究揭示了TGA在根生长和发育中的广泛作用并提供了机理上的解释。