Description
To protect themselves, plants have evolved a multilayered immune system for defense against viruses, including innate immunity and RNA silencing. Given that dsRNA can act as defense-inducing signals that can trigger sequence-specific RNA interference (RNAi) and non-specific pattern-triggered immunity (PTI), we hypothesize that both these pathways may be invoked via topical application of dsRNA, contributing to plant protection against viruses in dsRNA-treated crops. However, while the role of RNAi as a major antiviral mechanism during topical dsRNA applications is thoroughly investigated and proved, the molecular inputs and outputs of dsRNA-mediated PTI in plant antiviral protection is only just beginning to be unraveled. Therefore, we pursue to test the impact of exogenously applied dsRNA of viral sequences on both these layers of defense (RNAi and PTI), and explore its effect on the accumulation of different viruses, which share or not sequence homology with the dsRNA.
To investigate differences in gene expression underlying RNAi- and PTI-based antiviral defenses, we perform whole-transcriptome analysis by RNA-seq to capture changes in host transcripts occurring after topical application of dsRNA either alone or in the context of an antiviral response triggered by PTI and RNAi. We also investigate the hormonal components involved or required in the defense pathways activated by topically-applied dsRNA. Further, we hypothesize that viral proteins may act as PTI-suppressing effectors. Thus, we determine the effects of the expression of viral pathogenicity determinants on PTI responses triggered by dsRNA.
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