Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
University of Chinese Academy of Sciences, Beijing, China.
PLoS Genet. 2022 Mar 9;18(3):e1010090. doi: 10.1371/journal.pgen.1010090. eCollection 2022 Mar.
Nitrate can affect many aspects of plant growth and development, such as promoting root growth and inhibiting the synthesis of secondary metabolites. However, the mechanisms underlying such effects and how plants can integrate nitrate signals and root growth needs further exploration. Here, we identified a nitrate-inducible NAC family transcription factor (TF) NAC056 which promoted both nitrate assimilation and root growth in Arabidopsis. NAC056 is a nuclear-localized transcription activator, which is predominantly expressed in the root system and hypocotyl. Using the yeast one-hybrid assay, we identified the NAC056-specific binding sequence (NAC56BM), T [T/G/A] NCTTG. We further showed that the nac056 mutant compromised root growth. NAC056 overexpression promotes LR Initiation and nitrate deficiency tolerance. Using RNA sequencing analysis and in vitro biochemical experiment, we found NAC056 regulated the expression of genes required for NO3- assimilation, directly targeting the key nitrate assimilation gene NIA1. In addition, mutation of NIA1 suppresses LR development and nitrate deficiency tolerance in the 35S::NAC056 transgenic plants. Therefore, NAC056 mediates the response of plants to environmental nitrate signals to promote root growth in Arabidopsis.
硝酸盐可以影响植物生长和发育的许多方面，例如促进根生长和抑制次生代谢物的合成。然而，这种影响的机制以及植物如何整合硝酸盐信号和根生长需求仍需要进一步探索。在这里，我们鉴定了一个硝酸盐诱导的 NAC 家族转录因子（TF）NAC056，它可以促进拟南芥中硝酸盐的同化和根的生长。NAC056 是一种核定位的转录激活因子，主要在根系和下胚轴中表达。通过酵母单杂交实验，我们鉴定出 NAC056 特异性结合序列（NAC56BM），即 T [T/G/A] NCTTG。我们进一步表明，nac056 突变体损害了根的生长。NAC056 的过表达促进了侧根的起始和对硝酸盐缺乏的耐受性。通过 RNA 测序分析和体外生化实验，我们发现 NAC056 调节了硝酸盐同化所需基因的表达，直接靶向关键的硝酸盐同化基因 NIA1。此外，NIA1 的突变抑制了 35S::NAC056 转基因植物中侧根的发育和对硝酸盐缺乏的耐受性。因此，NAC056 介导了植物对环境硝酸盐信号的反应，以促进拟南芥中根的生长。
