Project description:Post-transcriptional regulation of mRNA mediated by methylation at the N6 position of adenine (N6-methyladenosine (m6A)) can have profound effects on transcriptome regulation in plants. Focused studies across eukaryotes offer glimpses into the processes governed by m6A throughout developmental and disease states. However, we lack an understanding of the dynamics and scope of regulatory potential m6A possesses during biotic stress responses in plants. Here, we provide a comprehensive look into the effects m6A has on both the short-term and long-term response to pathogenic stress in Arabidopsis. m6A deposition influences transcript abundance and stability on populations of stress-responsive transcripts. Additionally, we demonstrate a time- and stress-dependent modulation of m6A highlighting specific stress-responsive transcripts regulated directly and indirectly by this mark. As a result, m6A deficient plants are more resistant to bacterial pathogen Pseudomonas syringae infection, and this mark is essential in dictating and coordinating transcript fate during a biotic stress reprograming event. Overall, we show m6A is a critical aspect in modulating the post-transcriptional regulation of the transcriptome in response to pathogenic stress in plants.
Project description:By using RNA-seq analysis on purified extracellular vesicles from the infected tissue, we found that host plant Arabidopsis thaliana secretes a panel of messenger RNAs (mRNAs) in extracellular vesicles. These mobile plant mRNAs were delivered into cells of the interacting fungal pathogen Botrytis cinerea. While using Translating Ribosome Affinity Purification (TRAP) profiling and polysome analysis, we observed that the delivered host mRNAs were associated with active fungal polysomes isolated from the infected tissue, suggesting that they are translated in the fungal cells.
Project description:Oomycetes from the genus Phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. Due to particular physiological characteristics, no treatments against diseases caused by oomycetes are presently available. To develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between Phytophthora species and host plants. The present project is focused on the molecular mechanisms that underlie the compatible plant-oomycete interaction and plant disease.The laboratory developed a novel interaction system involving the model plant, Arabidopsis thaliana and Phytophthora parasitica, a soil-borne pathogen infecting a wide host range, thus representing the majority of Phytophthora species. A characteristic feature of the compatible Arabidopsis/Phytophthora parasitica interaction is an extended biotrophic phase, before infection becomes necrotrophic. Because the initial biotrophic phase is extremely short on natural (e.g. solanaceous) hosts, the Arabidopsis system provides the opportunity to analyze, for both interaction partners, the molecular events that determine the initiation of infection and the switch to necrotrophy.The present project aims at analyzing the compatible interaction between A. thaliana roots and Phytophthora parasitica. The Affymetrix A. thaliana full genome chip will be used to characterize modulations of the transcriptome occurring over a period of 24h from the onset of plant root infection to the beginning of necrotrophy. Parallel to this study, a custom designed Phytophthora parasitica biochip will enable analyzing of Phytophthora parasitica gene expression during the same stages. The pathosystem involving A. thaliana and Phytophthora parasitica was described in Attard A, Gourgues M, Callemeyn-Torre N, Keller H. 2010. The New phytologist 187: 449–460. The protocol for recovery of RNA from purified appressoria was described in Kebdani N, Pieuchot L, Deleury E, Panabieres F, Le Berre JY, Gourgues M. 2010. New Phytol 185: 248–257.
Project description:Oomycetes from the genus Phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. Due to particular physiological characteristics, no treatments against diseases caused by oomycetes are presently available. To develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between Phytophthora species and host plants. The present project is focused on the molecular mechanisms that underlie the compatible plant-oomycete interaction and plant disease.The laboratory developed a novel interaction system involving the model plant, Arabidopsis thaliana and Phytophthora parasitica, a soil-borne pathogen infecting a wide host range, thus representing the majority of Phytophthora species. A characteristic feature of the compatible Arabidopsis/Phytophthora parasitica interaction is an extended biotrophic phase, before infection becomes necrotrophic. Because the initial biotrophic phase is extremely short on natural (e.g. solanaceous) hosts, the Arabidopsis system provides the opportunity to analyze, for both interaction partners, the molecular events that determine the initiation of infection and the switch to necrotrophy.The present project aims at analyzing the compatible interaction between A. thaliana roots and Phytophthora parasitica. The Affymetrix A. thaliana full genome chip will be used to characterize modulations of the transcriptome occurring over a period of 24h from the onset of plant root infection to the beginning of necrotrophy. Parallel to this study, a custom designed Phytophthora parasitica biochip will enable analyzing of Phytophthora parasitica gene expression during the same stages. The pathosystem involving A. thaliana and Phytophthora parasitica was described in Attard A, Gourgues M, Callemeyn-Torre N, Keller H. 2010. The New phytologist 187: 449–460. The protocol for recovery of RNA from purified appressoria was described in Kebdani N, Pieuchot L, Deleury E, Panabieres F, Le Berre JY, Gourgues M. 2010. New Phytol 185: 248–257. A series of 14 hybridizations corresponding to two biological replicates each corresponding to RNA extractions of the following biological conditions were used: 1-Vegetative mycelium (recovered from two samples of 4 day-old cultures in liquid V8 medium at 24°C), 2- Motile zoospores (recovered from 8 independent cultures), 3-Appressoria differentiated on onion epidermis (epidermis from 20 onion bulbs inoculated with zoospores collected from 8 independent Petri dishes); appressoria collected 3 hours after inoculation (24 °C), 5- Infection of A. thaliana roots by Phytophthora parasitica zoospores (samples recovered at 2.5, 6, 10.5 and 30 hours post inoculation; 5 inoculated plants for each sample).
Project description:We performed a comparative study to determine the proteome of extracellular vesicles (EVs) from the cereal pathogen Fusarium graminearum (Fgr), recovered from in vitro cultures. Label-free quantitative proteomics was used to find significant enrichment of proteins between EV samples, the secretome (secreted-soluble proteins) and the cell lysate. Our results show that some proteins were exclusive to EVs and were upregulated compared to the secretome or cell lysate.