Sečnik Andrej, Volk Helena, Kunej Urban, Radišek Sebastjan, Štajner Nataša, Jakše Jernej
Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
Plant Protection Department, Slovenian Institute of Hop Research and Brewing, Žalec, Slovenia.
Microbiol Spectr. 2025 Jun 3;13(6):e0039424. doi: 10.1128/spectrum.00394-24. Epub 2025 Apr 16.
Viroids are small, naked, infectious single-stranded RNA molecules that exploit host factors to replicate. Some viroids have been linked to severe diseases in agricultural crops, including the recent outbreak of , previously known as Citrus bark cracking viroid (CBCVd), in hop plants (). Numerous studies have demonstrated the involvement of viroid-derived RNA in viroid pathogenesis through interactions with RNAi host factors, leading to alterations in gene expression, metabolism, and phenotype. Recent research efforts have also focused on elucidating viroid-induced changes in DNA methylation patterns via the RNA-directed DNA methylation pathway. In this study, we conducted an epigenome analysis of CBCVd-infected hop plants to provide novel evidence supporting the putative role of DNA methylation in CBCVd viroid pathogenesis. Our findings revealed that several genes involved in pathogen interaction pathways, such as MAPK signaling and LRR, exhibit hypomethylation, suggesting that their increased transcription enhances the host's ability to counteract the pathogen. Intriguingly, genes associated with RNA transcription and encoding key proteins, such as POL II, POL IV, and POL V, display hypermethylation, highlighting the significance of DNA methylation as a defense mechanism.IMPORTANCEViroids are emerging as a substantial threat to various crops; however, our understanding of the molecular mechanisms governing their pathogenesis and the host's defense remains incomplete. This knowledge gap leaves crop disease management reliant on unsustainable strategies. Our research seeks to address this issue by examining the complex world of infected hop plants. Specifically, we are investigating the DNA methylation processes, providing insights into the less-explored aspects of the host's response to viroid interaction. Our aim was to unravel the complexities of how viroids influence the molecular landscape within plants and the corresponding host defenses. By understanding these interactions, we hope to provide insights that lead to more sustainable ways to protect crops and keep agriculture resilient against viroid-related threats.
类病毒是小型、无包膜、具有感染性的单链RNA分子,它们利用宿主因子进行复制。一些类病毒与农作物的严重疾病有关,包括最近在啤酒花植株中爆发的[疾病名称],该疾病之前被称为柑橘树皮开裂类病毒(CBCVd)。大量研究表明,类病毒衍生的RNA通过与RNAi宿主因子相互作用参与类病毒致病过程,导致基因表达、代谢和表型发生改变。最近的研究工作还集中在通过RNA指导的DNA甲基化途径阐明类病毒诱导的DNA甲基化模式变化。在本研究中,我们对感染CBCVd的啤酒花植株进行了表观基因组分析,以提供新的证据支持DNA甲基化在CBCVd类病毒致病过程中的假定作用。我们的研究结果表明,一些参与病原体相互作用途径的基因,如MAPK信号通路和LRR,表现出低甲基化,这表明它们转录增加增强了宿主对抗病原体的能力。有趣的是,与RNA转录和编码关键蛋白(如POL II、POL IV和POL V)相关的基因显示出高甲基化,突出了DNA甲基化作为一种防御机制的重要性。
重要性
类病毒正成为对各种作物的重大威胁;然而,我们对其致病机制和宿主防御的分子机制的理解仍不完整。这一知识空白使得作物病害管理依赖于不可持续的策略。我们的研究旨在通过研究感染啤酒花植株的复杂情况来解决这一问题。具体而言,我们正在研究DNA甲基化过程,以深入了解宿主对类病毒相互作用反应中较少被探索的方面。我们的目标是揭示类病毒如何影响植物体内分子格局以及相应宿主防御的复杂性。通过理解这些相互作用,我们希望提供相关见解,从而找到更可持续的方法来保护作物,并使农业对类病毒相关威胁保持韧性。