Fig mosaic emaravirus p4 protein is involved in cell-to-cell movement

Area of Science:

• Plant virology
• Molecular biology
• Cell biology

Background:

• Fig mosaic virus (FMV) is an Emaravirus, a segmented negative-strand RNA virus.
• The FMV RNA4 segment encodes protein p4, presumed to be the movement protein (MP).
• Direct experimental evidence for FMV-p4's MP function was previously lacking.

Purpose of the Study:

• To experimentally determine the function of FMV-p4 as a movement protein.
• To investigate the intercellular localization and movement capabilities of FMV-p4.

Main Methods:

• Confocal laser scanning microscopy to assess FMV-p4 localization in plant cells.
• Functional assays to evaluate FMV-p4's ability to complement viral movement and facilitate intercellular transport.

Main Results:

• FMV-p4 was localized to plasmodesmata and plasma membrane, with associated tubule-like structures.
• FMV-p4 demonstrated the ability to complement viral cell-to-cell movement.
• FMV-p4 promoted GFP diffusion between cells and exhibited self-spreading to neighboring cells.

Conclusions:

• FMV-p4 functions as a viral movement protein.
• FMV-p4 shares characteristics with other viral MPs, playing a key role in cell-to-cell movement.
• These findings provide direct evidence for FMV-p4's role in viral dissemination.