Mutual association of Broad bean wilt virus 2 VP37-derived tubules and plasmodesmata obtained from cytological observation

Abstract

The movement protein VP37 of broad bean wilt virus 2 (BBWV 2) forms tubules in the plasmodesmata (PD) for the transport of virions between cells. This paper reports a mutual association between the BBWV 2 VP37-tubule complex and PD at the cytological level as determined by transmission electron microscopy. The generation of VP37-tubules within different PD leads to a different occurrence frequency as well as different morphology lines of virus-like particles. In addition, the frequency of VP37-tubules was different between PD found at different cellular interfaces, as well as between single-lined PD and branched PD. VP37-tubule generation also induced structural alterations of PD as well as modifications to the cell wall (CW) in the vicinity of the PD. A structural comparison using three-dimensional (3D) electron tomography (ET), determined that desmotubule structures found in the center of normal PD were absent in PD containing VP37-tubules. Using gold labeling, modification of the CW by callose deposition and cellulose reduction was observable on PD containing VP37-tubule. These cytological observations provide evidence of a mutual association of MP-derived tubules and PD in a natural host, improving our fundamental understanding of interactions between viral MP and PD that result in intercellular movement of virus particles.

Modeling the Reduction of Salmonella spp. on Chicken Breasts and Wingettes during Scalding for QMRA of the Poultry Supply Chain in China

“…The bacterial pellets were transferred into sterile 1.5 mL centrifuge tubes. Samples were fixed with 1 mL of 2.5% (v/v) glutaraldehyde (Sangon Biotech, Shanghai, China) and examined using a TEM as previously described [28].…”

Modeling the Reduction and Cross-Contamination of Salmonella in Poultry Chilling Process in China

“…The bacterial pellets were transferred into sterile 1.5 mL centrifuge tubes. Samples were fixed with 1 mL of 2.5% ( v/v ) glutaraldehyde (Sangon Biotech, Shanghai, China) and examined using a TEM as previously described [31].…”

Inspirations on Virus Replication and Cell-to-Cell Movement from Studies Examining the Cytopathology Induced by Lettuce infectious yellows virus in Plant Cells

“…Virus-encoded movement proteins (MPs) are required for viral cell-to-cell movement through PD. These can interact with other viral or host factors to target and modify PD by two main characterized mechanisms: ‘tubule-guided’ movement, which involves the extensive modification of PD into MP-lined tubules that mostly results in disappearance of DT and overall dilated PD pores [e.g., GFLV, Broad bean wilt virus (BBWV2) ( Xie et al, 2016 )]; ‘non-tubule-guided’ movement, in which viruses move through PD as virions or vRNPs by regulating the PD SEL and likely relying on the cellular machinery that transports macromolecules without inducing major PD structural changes (e.g., TMV, PVX, TuMV, BYV) ( Heinlein, 2015b ; Kumar et al, 2015 ; Rojas et al, 2016 ).…”

“…The microtubular cytoskeleton also seems to be involved in the transport of MP to the plasma membrane and the cell periphery, its inhibition results in MP accumulation in the cytoplasm ( Laporte et al, 2003 ). Furthermore, modification of the cell wall by callose deposition and cellulose reduction was observed on PD containing BBWV2 VP37-tubules via immunegold labeling and 3D ET construction ( Xie et al, 2016 ). Callose at the neck region of the PD plays an important role in the regulation of PD permeability, however, whether those modifications are associated with the formation or function of VP37-derived tubules are still unknown ( De Storme and Geelen, 2014 ; Tilsner et al, 2016 ).…”