Crosstalk between PTGS and TGS pathways in natural antiviral immunity and disease recovery 

First author: Camilla Julie Kørner; Affiliations: University of Basel (巴塞尔大学): Basel, Switzerland

Corresponding author: Manfred Heinlein

Virus-induced diseases cause severe damage to cultivated plants, resulting in crop losses. Certain plant–virus interactions allow disease recovery at later stages of infection and have the potential to reveal important molecular targets for achieving disease control. Although recovery is known to involve antiviral RNA silencing (抗病毒RNA沉默), the specific components of the many plant RNA silencing pathways required for recovery are not known. We found that Arabidopsis thaliana plants infected with oilseed rape mosaic virus (ORMV; 油菜花叶病毒) undergo symptom (症状) recovery. The recovered leaves contain infectious (有传染性的), replicating virus, but exhibit a loss of viral suppressor of RNA silencing (VSR; RNA沉默的病毒抑制子) protein activity. We demonstrate that recovery depends on the 21–22 nt siRNA-mediated post-transcriptional gene silencing (PTGS; 转录后基因沉默) pathway and on components of a transcriptional gene silencing (TGS; 转录基因沉默) pathway that is known to facilitate non-cell-autonomous (非细胞自发的) silencing signalling. Collectively, our observations indicate that recovery reflects the establishment of a tolerant state in infected tissues and occurs following robust delivery of antiviral secondary siRNAs from source to sink tissues, and establishment of a dosage able to block the VSR activity involved in the formation of disease symptoms.

病毒诱导的疾病会导致栽培植物的严重灾害，并导致作物的减产。在某些植物-病毒互作中，植物会在侵染的后期从疾病状态中恢复，该模式有助于寻找疾病控制的分子靶标。尽管已知恢复过程涉及抗病毒RNA沉默，然而恢复所必需的许多植物沉默通路的特异组分还不清楚。作者发现拟南芥在被油菜花叶病毒ORMV侵染后会出现症状的恢复。恢复的叶子中包含有传染性的、且能复制的病毒，但缺少了RNA沉默的病毒抑制子蛋白活性。作者的研究显示恢复过程依赖于21–22 nt的siRNA所介导的转录后基因沉默PTGS通路和能够促进非细胞自发沉默信号转导的转录水平基因沉默TGS通路组分。综上，本文的发现显示恢复反应了侵染组织中的抗性状态建立以及随后抗病毒次级siRNAs从源组织向库组织的传递，还有阻断参与疾病症状形成的VSR活性的剂量建立。

通讯：Manfred Heinlein (http://www.ibmp.cnrs.fr/annuaire/manfred-heinlein/)

个人简介：1992年，科隆大学，博士；1994-1997年，斯克里普斯研究所，博士后。

doi: 10.1038/s41477-018-0117-x

Journal: Nature Plants

Published online: 01 March, 2018

（P.S. 欢迎关注微信公众号：微信号Plant_Frontiers）