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:Phytophthora cinnamomi is a devastating soil-borne oomycete with a very broad host range however there remains a major gap in the understanding of plant resistance responses to the pathogen, furthermore, necrotrophic plant-pathogen interactions, particularly those of root pathogens, remain poorly understood. Zea mays exhibits non-host resistance to the pathogen and has been well characterised as a model species. Using the maize Affymetrix GeneChip array we conducted genome-wide gene expression profiling to elucidate the defence genes and pathways which are induced in the root tissue of a resistant plant species to the pathogen.
Project description:This study compares the response of wild type (A17) and ethylene insensitive mutant (sickle) lines of the model legume Medicago truncatula to infection by the root-infecting necrotrophic fungal pathogen, Rhizoctonia solani AG8 (WAC10335). Two time points were taken, 2 and 7 days after inoculation along with corresponding mock-treated controls.
Project description:Phytophthora cinnamomi is a devastating soil-borne oomycete with a very broad host range however there remains a major gap in the understanding of plant resistance responses to the pathogen, furthermore, necrotrophic plant-pathogen interactions, particularly those of root pathogens, remain poorly understood. Zea mays exhibits non-host resistance to the pathogen and has been well characterised as a model species. Using the maize Affymetrix GeneChip array we conducted genome-wide gene expression profiling to elucidate the defence genes and pathways which are induced in the root tissue of a resistant plant species to the pathogen. Each experimental repeat consisted of 60 Z. mays seedlings in total: 15 control and 15 inoculated plants per timepoint. Root tissue was harvested and snap frozen in liquid nitrogen and stored at -80°C until required. All harvested root tissue within each treatment group at each time point was pooled for total RNA extractions. Three technical repeats were conducted resulting in a total of 180 sampled plants and 12 samples of purified total RNA for microarray analysis. Total RNA was labelled, hybridised and scanned using standard Affymetrix protocols and resulted in 12 .CEL files. Raw data was processed using Partek Genomics Suite software and normalised using Robust Multi-Chip Average Software. Differentially expressed genes were defined by a fold difference of >1.5 (log2) and those with a P value cutoff of <0.05 were considered statistically significant.
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:To reveal transcriptome dynamics during adventitious root formation in a coniferous tree, C. japonica, we conducted custom microarry experiments. Three parts from cuttings of easy-to-root clone of C. japonica were collected at eight time points during adventitious root formation. The results revealed major turning points on transcriptome toward adventitious root formation and the expression behavior of genes related to carbohydrate, plant hormone and others suggested the important biological changes for adventitious root formation.
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).