No abstract

The replication-associated protein (RepA) of Maize streak virus interacts in yeast with retinoblastoma-related protein (RBR), the negative regulator of cell-cycle progression. This may allow geminiviruses to subvert cell-cycle control to provide an environment that is suitable for viral DNA replication. To determine the importance of this interaction for MSV infection, the RBR-binding motif, LxCxE, was mutated to IxCxE or LxCxK. Whilst RBR binding in yeast could not be detected for the LxCxK mutant, the IxCxE protein retained limited binding activity. Both mutants were able to replicate in maize cultures and to infect maize plants. However, whereas the wild-type virus invaded mesophyll cells of mature leaves, the LxCxK mutant was restricted to the vasculature, which is invaded prior to leaf maturity. Mature leaves contain high levels of RBR and it is suggested that the MSV RepA-RBR interaction is essential only in tissues with high levels of active RBR.

HighlightsFMDV is highly infectious and can only be handled in high-containment laboratories.This study has developed encapsidated control particles containing FMDV RNA.The construct contains target sequences for molecular assays used to detect FMDV.These control particles were evaluated using routine tests used for FMD diagnosis.These particles are non-infectious and temperature-stable.

It has proven possible to introduce foreign sequences into the genomes of plant viruses in such a way that their ability to replicate is retained. As a result, the foreign sequence is amplified resulting in either the high-level expression of a foreign protein or virus-induced gene silencing of an endogenous plant gene. This has meant that plant virus-based vectors have found widespread application both as a means of protein expression and as a tool in functional genomics.