Chen Xiaodong, Cheng Jingfei, Chen Lyuqin, Zhang Guifang, Huang Hai, Zhang Yijing, Xu Lin
National Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
National Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
Plant Physiol. 2016 Apr;170(4):2136-45. doi: 10.1104/pp.15.01733. Epub 2016 Feb 5.
Plants have powerful regenerative abilities that allow them to recover from damage and survive in nature. De novo organogenesis is one type of plant regeneration in which adventitious roots and shoots are produced from wounded and detached organs. By studying de novo root organogenesis using leaf explants of Arabidopsis (Arabidopsis thaliana), we previously suggested that wounding is the first event that provides signals to trigger the whole regenerative process. However, our knowledge of the role of wounding in regeneration remains limited. In this study, we show that wounding not only triggers the auxin-mediated fate transition of regeneration-competent cells, but also induces the NAC pathway for root tip emergence. The NAC1 transcription factor gene was specifically expressed in response to wounding in the leaf explant, but not in the wounded leaf residue of the source plant. Inhibition of the NAC1 pathway severely affected the emergence of adventitious root tips. However, the NAC1 pathway functioned independently of auxin-mediated cell fate transition and regulates expression of CEP genes, which encode proteins that might have a role in degradation of extensin proteins in the cell wall. Overall, our results suggest that wounding has multiple roles in de novo root organogenesis and that NAC1 acts as one downstream branch in regulating the cellular environment for organ emergence.
植物具有强大的再生能力，使其能够从损伤中恢复并在自然环境中存活。从头器官发生是植物再生的一种类型，其中不定根和不定芽从受伤和脱离的器官中产生。通过使用拟南芥（Arabidopsis thaliana）的叶片外植体研究从头根器官发生，我们之前提出创伤是提供信号触发整个再生过程的第一个事件。然而，我们对创伤在再生中的作用的了解仍然有限。在本研究中，我们表明创伤不仅触发了生长素介导的再生能力细胞的命运转变，还诱导了根尖出现的NAC途径。NAC1转录因子基因在叶片外植体中对创伤有特异性表达，但在源植物受伤的叶片残体中不表达。抑制NAC1途径严重影响不定根尖的出现。然而，NAC1途径独立于生长素介导的细胞命运转变发挥作用，并调节CEP基因的表达，CEP基因编码的蛋白质可能在细胞壁中伸展蛋白的降解中起作用。总体而言，我们的结果表明创伤在从头根器官发生中具有多种作用，并且NAC1作为调节器官出现的细胞环境的一个下游分支发挥作用。
