A Thioredoxin Domain-Containing Protein Interacts with Pepino mosaic virus Triple Gene Block Protein 1

Abstract

Pepino mosaic virus (PepMV) is a mechanically-transmitted tomato pathogen of importance worldwide. Interactions between the PepMV coat protein and triple gene block protein (TGBp1) with the host heat shock cognate protein 70 and catalase 1 (CAT1), respectively, have been previously reported by our lab. In this study, a novel tomato interactor (SlTXND9) was shown to bind the PepMV TGBp1 in yeast-two-hybrid screening, in vitro pull-down and bimolecular fluorescent complementation (BiFC) assays. SlTXND9 possesses part of the conserved thioredoxin (TRX) active site sequence (W__PC vs. WCXPC), and TXND9 orthologues cluster within the TRX phylogenetic superfamily closest to phosducin-like protein-3. In PepMV-infected and healthy Nicotiana benthamiana plants, NbTXND9 mRNA levels were comparable, and expression levels remained stable in both local and systemic leaves for 10 days post inoculation (dpi), as was also the case for catalase 1 (CAT1). To localize the TXND9 in plant cells, a polyclonal antiserum was produced. Purified α-SlTXND9 immunoglobulin (IgG) consistently detected a set of three protein bands in the range of 27–35 kDa, in the 1000 and 30,000 g pellets, and the soluble fraction of extracts of healthy and PepMV-infected N. benthamiana leaves, but not in the cell wall. These bands likely consist of the homologous protein NbTXND9 and its post-translationally modified derivatives. On electron microscopy, immuno-gold labelling of ultrathin sections of PepMV-infected N. benthamiana leaves using α-SlTXND9 IgG revealed particle accumulation close to plasmodesmata, suggesting a role in virus movement. Taken together, this study highlights a novel tomato-PepMV protein interaction and provides data on its localization in planta. Currently, studies focusing on the biological function of this interaction during PepMV infection are in progress.

RNA-Seq Transcriptome Analysis Provides Candidate Genes for Resistance to Tomato Leaf Curl New Delhi Virus in Melon

“…This gene family is associated with JA-SA pathway ( Li et al, 2017c ), and moreover, MELO3C022339.2 is an ortholog to the Thioredoxin superfamily proteins of A. thaliana . Thioredoxin proteins are described as interacting with begomoviruses and also impairing resistance to potyviruses ( Luna-Rivero et al, 2016 ; Liu et al, 2017 ; Mathioudakis et al, 2018 ). In response to TYLCV, thioredoxin and TCP proteins in tomato interact with TFs that regulate defense mechanisms ( Huang et al, 2016 ).…”

Analysis of proteomic changes in cassava cv. Kasetsart 50 caused by Sri Lankan cassava mosaic virus infection

“…Pattern recognition receptors (PRRs) are activated upon detecting predetermined molecular structures, leading to the initiation of PAMP-triggered immunity (PTI) that can prevent the entry of most invading organisms [ 84 ]. Recent research has shown that viruses can both stimulate and repress PTI-like mechanisms [ 85 – 99 ]. In some instances, pathogen-derived molecular structures suppress protective mechanisms.…”

“…In Nicotiana tabacum , TRXh3 confers resistance to Tobacco mosaic virus (TMV) and Cucumber mosaic virus (CMV) [ 97 ] and in maize TRX mediates early resistance against the Sugarcane mosaic virus [ 98 ]. Using yeast-two-hybrid screening combined with invitro pull-down and biomolecular fluorescent complementation (BiFC) assays, Mathioudakis et al [ 99 ] reported that thioredoxin (TRX) in tomato plants interacted with the pepino mosaic virus (PepMV) coat protein, triple gene block protein (TGBp1), heat shock cognate protein 70, and catalase 1 (CAT1). In our study, STICH analysis predicted the interaction of TRX combined with glutamate synthetase 1 and 2 (GLT1 and 2), potentially affecting glutamate biosynthesis.…”

Roles of ROS and redox in regulating cell-to-cell communication: Spotlight on viral modulation of redox for local spread

“…N. tabacum transgenic lines constitutively expressing the chloroplast-localized NtTRXh3 showed increased resistance to TMV and Cucumber mosaic virus (CMV), whereas silencing this gene led to suppressed defense responses, and increased accumulation of both viruses (Sun et al, 2010). There are other examples where viral proteins were reported to interact with differentTRX members, such as TGBp1 from Pepino mosaic virus with the tomato TRX SlTXND9 (Mathioudakis et al, 2018), and TRX-like proteins from whitefly with the coat proteins of two begomoviruses (Saurav et al, 2019). However, their exact roles in the context of host-virus interactions remain unexplored.…”