Immune gene activation by NPR and TGA transcriptional regulators in the model monocot Brachypodium distachyon

第一作者：Kohei Shimizu

通讯单位：东京科技大学

通讯作者：Gen-Ichiro Arimura

背景介绍：The nonexpressor of pathogenesis-related (NPR) gene family is well known to play a crucial role in transactivation of TGA transcription factors for salicylic acid (SA)-responsive genes, including pathogenesis-related protein 1 (PR1), during plants' immune response after pathogen attack in the model dicot Arabidopsis thaliana. 

病程相关(NPR)基因家族的非表达因子在双子叶拟南芥病原菌侵袭后植物免疫应答过程中，对水杨酸(SA)应答基因的TGA转录因子的反式激活起着至关重要的作用。

提出问题：However, little is known about NPR gene functions in monocots. We therefore explored the functions of NPRs in SA signaling in the model monocot Brachypodium distachyon. 

然而，对NPR基因在单子叶植物中的功能知之甚少。因此，我们探索了NPR在单子叶短柄藻远隔中SA信号转导中的作用。

研究结果#1：BdNPR1 and BdNPR2/3 share structural similarities with A. thaliana AtNPR1/2 and AtNPR3/4 subfamilies, respectively. The transcript level of BdNPR2 but not BdNPR1/3 appeared to be positively regulated in leaves in response to methyl salicylate. Reporter assays in protoplasts showed that BdNPR2 positively regulated BdTGA1-mediated activation of PR1. This transactivation occurred in an SA-dependent manner through SA binding at Arg468 of BdNPR2.

BdNPR1和BdNPR2/3分别与拟南芥AtNPR1/2和AtNPR3/4亚家族结构相似。水杨酸甲酯对BdNPR2的转录水平有正向调节作用，但对BdNPR1/3的转录水平无明显影响。原生质体中的报告分析表明，BdNPR2正向调节BdTGA1介导的PR1的激活。这种反式激活通过BdNPR2的Arg468上的SA结合以SA依赖的方式发生。

结果#2： In contrast, BdNPR1 functioned as a suppressor of BdNPR2/BdTGA1-mediated transcription of PR1. 

相反，BdNPR1对BdNPR2/BdTGA1介导的PR1转录具有抑制作用。

结论：Collectively, our findings reveal that the TGA-promoted transcription of SA-inducible PR1 is orchestrated by the activator BdNPR2 and the repressor BdNPR1, which function competitively in B. distachyon.

综上所述，我们的发现表明，TGA促进的SA诱导的PR1的转录是由激活因子BdNPR2和抑制因子BdNPR1协调的，这两个因子在B.disachyon中具有竞争性功能。

原文链接：https://onlinelibrary.wiley.com/doi/epdf/10.1111/tpj.15681?saml_referrer

作者简介：

1998-2002 Graduate School of Agriculture, Kyoto University, Postdoctoral Fellowship

2002-2004 University of British Columbia, Postdoctoral Fellowship

2004-2005 Max Planck Institute for Chemical Ecology, Postdoctoral Fellowship

2005-2008 Max Planck Institute for Chemical Ecology, Junior Group Leader

2008-2012 Graduate school of Science, Kyoto University, Associate Professor

2010- International Master in Horticultural Science (IMaHS), University of Bologna, Specific Teaching Professor

2012-2013 Center of Ecological Reseearch, Kyoto University, Associate Professor

2013- Faculty of Industrial Science & Technology, Tokyo University of Science, Associate Professor

Journal: Plant Journal 

Published date: January 21, 2022