Project description:Metagenome data from soil samples were collected at 0 to 10cm deep from 2 avocado orchards in Channybearup, Western Australia, in 2024. Amplicon sequence variant (ASV) tables were constructed based on the DADA2 pipeline with default parameters.
Project description:Plant viruses rely on both host plant and vectors for a successful infection. This study investigated the global transcriptomic changes in Arabidopsis thaliana that were simultaneously exposed to both a plant virus (turnip yellows virus, polerovirus genus and Solemoviridae family) and its aphid vector (Myzus persicae). Some of these modifications in gene expression may promote in a timely manner viral transmission and dispersion.
Project description:The movement of virus-derived (v)siRNAs between plant cells has prompted the widely held assumption that they help immunize as-yet-uninfected tissues. Ascertaining this role is challenging because it requires uncoupling vsiRNA mobility from viral movement while preserving viral virulence. Consequently, the contribution of non-cell-autonomous RNAi to plant antiviral immunity remains essentially unknown. Here, we investigated the naturally phloem-restricted infection of turnip yellows virus (TuYV) in the stereotypical Arabidopsis root system at cellular resolution. We uncovered intertwined, complex mechanisms operating in both vsiRNA-emitting and -recipient cells, that drive reiterated short-range (~3-4 cell) immunization events. We found that, while intracellular antiviral RNAi is nullified by TuYV, non-cell-autonomous immunization accounts mainly —if not exclusively— for the containment of viral tissue invasion, titers and symptoms severity at the whole-plant scale. Mobile vsiRNA-mediated immunization likewise spatially confines a TuYV unrelated virus over ~3-4 cells, uncovering a generic, essential, yet previously unexplored component of plant antiviral defence.
Project description:In plants and some animal lineages, RNA silencing is an efficient and adaptable defense mechanism against viruses. To counter it, viruses encode suppressor proteins that interfere with RNA silencing. Phloem-restricted viruses are spreading at an alarming rate and cause substantial reduction of crop yield, but how they interact with their hosts at the molecular level is still insufficiently understood. Here, we investigate the antiviral response against phloem-restricted turnip yellows virus (TuYV) in the model plant Arabidopsis thaliana. Using a combination of genetics, deep sequencing, and mechanical vasculature enrichment, we show that the main axis of silencing active against TuYV involves 22-nt vsiRNA production by DCL2, and their preferential loading into AGO1. Moreover, we identify vascular secondary siRNA produced from plant transcripts and initiated by DCL2-processed AGO1-loaded vsiRNA Unexpectedly, and despite the viral encoded VSR P0 previously shown to mediate degradation of AGO proteins, vascular AGO1 undergoes specific post-translational stabilization during TuYV infection. Collectively, our work uncovers the complexity of antiviral RNA silencing against phloem-restricted TuYV and prompts a re-assessment of the role of its suppressor of silencing P0 during genuine infection.
