In the ever-evolving battle against plant viruses, a recent study published in the journal ‘Viruses’ has shed new light on the intricate workings of the tomato zonate spot virus (TZSV), offering promising avenues for future control strategies. The research, led by Xingyue Zhao from the Hunan Plant Protection Institute, has uncovered the complex interaction network between the virus’s proteins and their roles in facilitating viral movement within infected plants.
TZSV poses a significant threat to agriculture, particularly to tomato crops, causing substantial yield losses. Understanding the functional roles and interactions of its encoded proteins is crucial for developing effective control measures. The study focused on the interaction network between the TZSV nucleocapsid (N), the non-structural M-segment (NSm), and the non-structural S-segment (NSs) proteins, with a particular emphasis on the functional characterization of the NSm protein.
Using a combination of yeast two-hybrid (Y2H) analysis, bimolecular fluorescence complementation (BiFC), and luciferase complementation imaging (LCI) assays, the researchers confirmed that both the N protein and the NSm protein exhibit self-interaction. Moreover, they detected heterologous interactions between NSs-N, N-NSm, and NSs-NSm. These interactions were found to occur in specific cellular locations, with N-N and NSm-N interactions happening in both the cytoplasm and nucleus, while NSm-NSm interaction was confined to the nucleus. Interestingly, NSs-N and NSs-NSm interactions were observed only in the cytoplasm.
The study also revealed that the NSm protein specifically targets plasmodesmata (PD), the channels that connect plant cells, and co-localizes with the known PD marker protein PDLP8. This finding is significant as it suggests that NSm plays a crucial role in facilitating viral movement between cells. To test this hypothesis, the researchers demonstrated that TZSV NSm could mediate the cell-to-cell movement of a cucumber mosaic virus mutant lacking its native movement protein. This was evidenced by the spread of fluorescent foci to neighboring cells, observed at six days post-inoculation.
“The NSm protein of TZSV is a functional movement protein essential for facilitating viral intercellular transport,” said lead author Xingyue Zhao. “This promotes viral spread within the host during systemic infection.”
The implications of this research for the agriculture sector are substantial. By understanding the mechanisms by which TZSV spreads within plants, researchers can develop targeted control strategies. These could include the development of resistant crop varieties or the use of genetic engineering to disrupt the virus’s movement proteins.
“This study comprehensively describes the intricate interaction network between the N, NSm, and NSs proteins of TZSV and clarifies their subcellular localizations within plant cells,” Zhao added. “These findings offer important insights into the infection mechanism of TZSV and provide potential targets for the control of this devastating virus.”
As the global population continues to grow, the demand for food increases, making it more important than ever to protect our crops from viral threats. The research led by Xingyue Zhao and his team at the Hunan Plant Protection Institute represents a significant step forward in this endeavor, offering hope for more effective control of TZSV and other plant viruses in the future.