Department of Plant Pathology and Microbiology and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA.
Department of Plant Pathology and Microbiology and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA; Department of Biochemistry and Biophysics and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China.
Cell Rep. 2019 Aug 20;28(8):2194-2205.e6. doi: 10.1016/j.celrep.2019.07.054.
Proper transcriptome reprogramming is critical for hosts to launch an effective defense response upon pathogen attack. How immune-related genes are regulated at the posttranscriptional level remains elusive. We demonstrate here that P-bodies, the non-membranous cytoplasmic ribonucleoprotein foci related to 5'-to-3' mRNA decay, are dynamically modulated in plant immunity triggered by microbe-associated molecular patterns (MAMPs). The DCP1-DCP2 mRNA decapping complex, a hallmark of P-bodies, positively regulates plant MAMP-triggered responses and immunity against pathogenic bacteria. MAMP-activated MAP kinases directly phosphorylate DCP1 at the serine residue, which further stimulates its interaction with XRN4, an exonuclease executing 5'-to-3' degradation of decapped mRNA. Consequently, MAMP treatment potentiates DCP1-dependent mRNA decay on a specific group of MAMP-downregulated genes. Thus, the conserved 5'-to-3' mRNA decay elicited by the MAMP-activated MAP kinase cascade is an integral part of plant immunity. This mechanism ensures a rapid posttranscriptional downregulation of certain immune-related genes that may otherwise negatively impact immunity.
正确的转录组重编程对于宿主在病原体攻击时发起有效的防御反应至关重要。免疫相关基因如何在转录后水平受到调节仍然难以捉摸。我们在这里证明，与 5'-to-3' mRNA 降解相关的非膜细胞质核糖核蛋白聚集体 P 体在微生物相关分子模式 (MAMP) 触发的植物免疫中动态调节。DCP1-DCP2 mRNA 脱帽复合物是 P 体的标志，它正向调节植物 MAMP 触发的反应和对病原菌的免疫。MAMP 激活的 MAP 激酶直接在丝氨酸残基上磷酸化 DCP1，进一步刺激其与 XRN4 的相互作用，后者是执行 5'-to-3'降解去帽 mRNA 的外切酶。因此，MAMP 处理增强了 DCP1 依赖性的特定一组 MAMP 下调基因的 mRNA 降解。因此，由 MAMP 激活的 MAP 激酶级联引发的保守的 5'-to-3' mRNA 降解是植物免疫的一个组成部分。该机制确保了某些免疫相关基因的快速转录后下调，否则这些基因可能会对免疫产生负面影响。
