Project description:Seedlings grown from seeds from open-pollinated mother trees of genotype UF12 were grown and at two months of age used to analyze response to treatment with the fungal pathogen Colletotrichum theobromicola and the oomycete pathogen Phytophthora palmivora.
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:Here, we define the proteomic response of the early divergent liverwort Marchantia polymorpha during infection with the oomycete pathogen Phytophthora palmivora. We sampled whole liverwort thalli that were mock-inoculated (water) or infected with P. palmivora zoospores at 4 and 8 days post inoculation (dpi). This analysis revealed the protein profiles of liverworts during the biotrophic (4 dpi) and necrotrophic (8 dpi) stages of pathogen infection. In combination with additional omics datasets, our analyses reveal conserved aspects in the molecular response to pathogen infection in liverworts and angiosperms.
Project description:Cacao (Theobroma cacao) is a highly valuable crop with growing demands in the global market. However, cacao farmers often face challenges posed by black pod disease caused by Phytophthora spp. with P. palmivora as the most dominant. Regulations of various gene expression influence plant resistance to pathogens. One mechanism involves targeting mRNA of virulence genes in the invading pathogens, suppressing their infection. However, resistance also could be suppressed by plant-derived miRNAs that target their own defense genes. The objective of this study is to identify differentially expressed miRNAs in black pod resistant and susceptible Cacao varieties and to predict their targets in T. cacao and P. palmivora transcripts. In our research, 54 known miRNAs from 40 miRNA families and 67 Novel miRNAs were identified. As much as 17 miRNAs were differentially expressed in susceptible variety compared to resistant one, with 9 miRNAs were upregulated and 8 miRNAs downregulated. In T. cacao transcripts, the upregulated miRNAs were predicted to target several genes, including defense genes. The suppression of these defense genes can lead to a reduction in plant resistance against pathogen infection. While in P. palmivora transcripts, the upregulated miRNAs were predicted to target several genes, including P. palmivora effector genes and other important metabolism activities genes. In the future, limiting expression of miRNAs that target T. cacao's defense genes and applying miRNAs that target P. palmivora effector genes hold promise for enhancing cacao plant resistance against P. palmivora infection.
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:Transcriptome response of avocado roots subjected to flooding, infection by the oomycete Phytophthora cinnamomi or a combination of both. Analysis was carried out at two time-points. Aim was to identify important genes in response to these stresses.