Foret Jessica, Kim Jung-Gun, Sattely Elizabeth S, Mudgett Mary Beth
Department of Biology, Stanford University, Stanford, CA 94305, USA.
Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
Plant Physiol. 2024 Dec 23;197(1). doi: 10.1093/plphys/kiae544.
N-Hydroxy-pipecolic acid (NHP) is a mobile metabolite essential for inducing and amplifying systemic acquired resistance (SAR) following a pathogen attack. Early phases of NHP signaling leading to immunity have remained elusive. Here, we report the early transcriptional changes mediated by NHP and the role salicylic acid (SA) plays during this response in Arabidopsis (Arabidopsis thaliana). We show that distinct waves of expression within minutes to hours of NHP treatment include increased expression of WRKY transcription factor genes as the primary transcriptional response, followed by the induction of WRKY-regulated defense genes as the secondary response. Most genes induced by NHP within minutes were SA dependent, whereas those induced within hours were SA independent. These data suggest that NHP induces the primary transcriptional response under basal levels of SA and that new SA biosynthesis via ISOCHORISMATE SYNTHASE 1/SA-INDUCTION DEFICIENT 2 is dispensable for inducing the secondary transcriptional response. We demonstrate that WRKY70 is required for the induced expression of a set of genes defining some of the secondary transcriptional response, SAR protection, and NHP-dependent enhancement of reactive oxygen species production in response to flagellin treatment. Our study highlights the key genes and pathways defining early NHP responses and the role of WRKY70 in regulating NHP-dependent transcription.
N-羟基哌啶酸（NHP）是一种动态代谢产物，在病原体攻击后诱导和放大系统获得性抗性（SAR）中必不可少。NHP信号传导导致免疫的早期阶段仍不清楚。在这里，我们报告了NHP介导的早期转录变化以及水杨酸（SA）在拟南芥（Arabidopsis thaliana）这种反应过程中所起的作用。我们表明，在NHP处理后的数分钟到数小时内，不同的表达波包括WRKY转录因子基因表达增加作为主要转录反应，随后诱导WRKY调控的防御基因作为次要反应。NHP在数分钟内诱导的大多数基因依赖于SA，而在数小时内诱导的那些基因则不依赖于SA。这些数据表明，NHP在SA的基础水平下诱导主要转录反应，并且通过异分支酸合酶1/SA诱导缺陷2进行的新的SA生物合成对于诱导次要转录反应是可有可无的。我们证明，WRKY70是一组定义一些次要转录反应、SAR保护以及响应鞭毛蛋白处理时NHP依赖性活性氧产生增强的基因诱导表达所必需的。我们的研究突出了定义早期NHP反应的关键基因和途径以及WRKY70在调节NHP依赖性转录中的作用。
