Gene silencing as an adaptive defence against viruses

Strong host resistance targeted against a viral suppressor of the plant gene silencing defence mechanism.

The 2b protein encoded by cucumber mosaic cucumovirus (Cmv2b) acts as an important virulence determinant by suppressing post-transcriptional gene silencing (PTGS), a natural plant defence mechanism against viruses. We report here that the tomato aspermy cucumovirus 2b protein (Tav2b), when expressed from the unrelated tobacco mosaic tobamovirus (TMV) RNA genome, activates strong host resistance...

Mutualistic ants as an indirect defence against leaf pathogens.

Mutualistic ants are commonly considered as an efficient indirect defence against herbivores. Nevertheless, their indirect protective role against plant pathogens has been scarcely investigated. We compared the protective role against pathogens of two different ant partners, a mutualistic and a parasitic ant, on the host plant Acacia hindsii (Fabaceae). The epiphytic bacterial community on leav...

The evolution of RNAi as a defence against viruses and transposable elements

RNA interference (RNAi) is an important defence against viruses and transposable elements (TEs). RNAi not only protects against viruses by degrading viral RNA, but hosts and viruses can also use RNAi to manipulate each other's gene expression, and hosts can encode microRNAs that target viral sequences. In response, viruses have evolved a myriad of adaptations to suppress and evade RNAi. RNAi ca...

Gene Silencing I A virus defence pathway and a technology

Autophagy as a defence against intracellular pathogens.

Autophagy is a membrane trafficking pathway that results in the formation of autophagosomes which deliver portions of the cytosol to lysosomes for degradation. When autophagosomes engulf intracellular pathogens, the pathway is called 'xenophagy' because it leads to the removal of foreign material. Autophagy is activated during infection by Toll-like receptors that recognize pathogen-associated ...