Barley stripe mosaic virus γb protein disrupts chloroplast antioxidant defenses to optimize viral replication. (13th July 2021)

• Record Type: Journal Article
• Authors: Wang, Xueting; Jiang, Zhihao; Yue, Ning; Jin, Xuejiao; Zhang, Xuan; Li, Zhaolei; Zhang, Yongliang; Wang, Xian‐Bing; Han, Chenggui; Yu, Jialin; Li, Dawei
• Is Part Of: EMBO journal. Volume 40:Number 16(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-13
• Subjects: 2‐Cys Prx -- chloroplast antioxidant defenses -- NTRC -- Viral replication -- γb protein; Molecular biology -- Periodicals; 572.805
• DOI: 10.15252/embj.2021107660
• Languages: English
• ISSNs: 0261-4189

Abstract

Abstract: The plant antioxidant system plays important roles in response to diverse abiotic and biotic stresses. However, the effects of virus infection on host redox homeostasis and how antioxidant defense pathway is manipulated by viruses remain poorly understood. We previously demonstrated that the Barley stripe mosaic virus (BSMV) γb protein is recruited to the chloroplast by the viral αa replicase to enhance viral replication. Here, we show that BSMV infection induces chloroplast oxidative stress. The versatile γb protein interacts directly with NADPH‐dependent thioredoxin reductase C (NTRC), a core component of chloroplast antioxidant systems. Overexpression of NbNTRC significantly impairs BSMV replication in Nicotiana benthamiana plants, whereas disruption of NbNTRC expression leads to increased viral accumulation and infection severity. To counter NTRC‐mediated defenses, BSMV employs the γb protein to competitively interfere with NbNTRC binding to 2‐Cys Prx. Altogether, this study indicates that beyond acting as a helicase enhancer, γb also subverts NTRC‐mediated chloroplast antioxidant defenses to create an oxidative microenvironment conducive to viral replication. SYNOPSIS: The Barley stripe mosaic virus (BSMV) γb protein promotes viral infection in plants via various mechanisms. This work reveals an additional role in disrupting chloroplast antioxidant defenses to create an oxidative microenvironment conducive to viral replication. BSMV infection disturbs chloroplast redox homeostasis and induces oxidative stress. The BSMV γb protein directly interacts with host NADPH‐dependent thioredoxin reductase C (NTRC) at chloroplasts. NTRC expression suppresses BSMV replication in Nicotiana benthamiana . γb protein competitively interferes with NTRC binding to 2‐Cys peroxiredoxins. Abstract : Inhibition of the chloroplast‐localized NADPH‐dependent thioredoxin reductase C to create an oxidative microenvironment promotes plant infection by a chloroplast‐replicating virus.