Involvement of the chloroplast gene ferredoxin 1 in multiple responses of Nicotiana benthamiana to Potato virus X infection

Abstract

The chloroplast protein ferredoxin 1 (FD1), with roles in the chloroplast electron transport chain, is known to interact with the coat proteins (CPs) of Tomato mosaic virus and Cucumber mosaic virus. However, our understanding of the roles of FD1 in virus infection remains limited. Here, we report that the Potato virus X (PVX) p25 protein interacts with FD1, whose mRNA and protein levels are reduced by PVX infection or by transient expression of p25. Silencing of FD1 by Tobacco rattle virus-based virus-induced gene silencing (VIGS) promoted the local and systemic infection of plants by PVX. Use of a drop-and-see (DANS) assay and callose staining revealed that the permeability of plasmodesmata (PDs) was increased in FD1-silenced plants together with a consistently reduced level of PD callose deposition. After FD1 silencing, quantitative reverse transcription–real-time PCR (qRT–PCR) analysis and LC-MS revealed these plants to have a low accumulation of the phytohormones abscisic acid (ABA) and salicylic acid (SA), which contributed to the decreased callose deposition at PDs. Overexpression of FD1 in transgenic plants manifested resistance to PVX infection, but the contents of ABA and SA, and the PD callose deposition were not increased in transgenic plants. Overexpression of FD1 interfered with the RNA silencing suppressor function of p25. These results demonstrate that interfering with FD1 function causes abnormal plant hormone-mediated antiviral processes and thus enhances PVX infection.

Downregulation of Light-Harvesting Complex II Induces ROS-Mediated Defense Against Turnip Mosaic Virus Infection in Nicotiana benthamiana

“…(B) Relative expression level of NbLHCB3 in the NbLHCB3 -silenced plants. (C) The chlorophyll contents [measured as described before ( Yang et al, 2020 )] were reduced in the NbLHCB3 -silenced plants. (D) Detection of TuMV RNAs and CP protein accumulation in plants inoculated with TRV:LHCB3 or TRV:00 at 4 dpi.…”

Genome-Wide Identification Reveals That Nicotiana benthamiana Hypersensitive Response (HR)-Like Lesion Inducing Protein 4 (NbHRLI4) Mediates Cell Death and Salicylic Acid-Dependent Defense Responses to Turnip Mosaic Virus

“…Coimmunoprecipitation (Co-IP) assays were conducted as previously described ( Yang X. et al, 2019 ; Chen B. et al, 2020 ). PCV-NbHRLI4-flag was coexpressed with PCV-TuMV-P3-GFP, PCV-TuMV-P3C-GFP, PCV-TuMV-P3N-GFP, PCV-TuMV-P3N-PIPO-GFP, or PCV-GUS-GFP in equal volumes (OD 600 = 1.0) and infiltrated into leaves.…”

“…The plant tissues expressing proteins were imaged using Leica TCS SP5 confocal microscope (Leica Microsystems, Bannockburn, IL, United States). The BiFC assays were carried out as previously described (Yang X. et al, 2019;Jiang et al, 2020). NbHRLI4 and its mutants were fused with an N-terminal fragment of YFP, while TuMV-P3, TuMV-P3C, TuMV-P3N, and TuMV-P3N-PIPO were fused with a C-terminal fragment of YFP.…”

Plasmodesmata-Involved Battle Against Pathogens and Potential Strategies for Strengthening Hosts

“…Nevertheless, particular plant viral proteins can interact with chloroplast proteins to impair the defense of hosts and facilitate the infection of virus (Zhao et al, 2016 ; Bhattacharyya and Chakraborty, 2018 ). During Potato virus X (PVX) infection, the viral p25 protein interacts with the chloroplast protein ferredoxin 1 (FD1) to reduce its mRNA and protein levels, resulting in a dramatic decrease of PD callose accumulation that is probably associated with the reduction in phytohormones abscisic acid (ABA) and salicylic acid (SA) (Yang et al, 2020 ). Arabidopsis INCREASED SIZE EXCLUSION LIMIT ( ISE ) 2 encodes a chloroplast DEAH RNA helicase, whose mutation increases the branched PD formation and intercellular trafficking (Kobayashi et al, 2007 ).…”