This project aims at identifying the pathogenicity effectors of the obligate biotrophic oomycete Plasmopara halstedii, the agent of sunflower downy mildew, and exploiting them in the search for durable resistance to the disease in the cultivated sunflower, Helianthus annuus.
Our objectives are: (i) to define the repertoire of secreted and in planta translocated effectors (RXLR and CRN) of P.halstedii pathotypes, to exploit (ii) the effector variability between pathotypes in order to characterize avirulence genes or (iii) the conservation of effectors between pathotypes to identify more sustainable resistance sources to sunflower mildew, a major agricultural issue.
Dr. Laurence Godiard, CR1 INRA, HDR (PI)
Laurence Godiard did her PhD in 1992 at the University of Toulouse III on the characterization of Tobacco genes induced during the hypersensitive response to the bacterial phytopathogen, Ralstonia solanacearum. She then moved as a post-doc fellow to the group of Jeffery Dangl, at Max Planck Institute of Cologne (Germany) where she cloned by map-based cloning approach together with Dr. Murray Grant, the Arabidopsis thaliana RPM1 gene, one of the first NBS-LRR Resistance genes to be cloned. When she joined the INRA in 1995 as a permanent scientist in the group of Yves Marco/Dominique Roby, she initiated and characterized a new quantitative disease resistance of A.thaliana to a temperate isolate of Ralstonia solanacearum, the agent of bacterial wilt, found in France. At this time she evolved a major interest in the power of transcriptomics and joined the starting group of Pascal Gamas, she constructed and analyzed suppression subtractive hybridization (SSH) libraries of Medicago truncatula, in order to find novel plant nodulation regulatory genes. She then studied one of these genes encoding a putative basic Helix Loop Helix (bHLH) transcription factor and showed that this gene up- regulated from early to late nodulation stages encodes an original protein involved in nodule vascular patterning and nodule to plant metabolic exchanges. The research work of L. Godiard switched then back to plant pathogen interactions in the sunflower team led at the time by Patrick Vincourt. She is responsible since 2008 for the project on sunflower downy mildew caused by the obligate biotrophic oomycete, Plasmopara halstedii, around two main axes: the identification of the pathogen effectors, and their use in the characterization of broad and potentially sustainable resistance in sunflower (ANR EFFECTOORES). In 2015, she obtained a PROMOSOL funding over 3 years to build a collection of isolates of Plasmopara halstedii, to set molecular markers of pathotypes, and to map new resistances to downy mildew in sunflower.
Dr Yann Pecrix, post-doctoral fellow ANR EFFECTOORES (2015-2016)
Charlotte Penouilh, CDD PROMOSOL (2015-2016)
Charlotte Penouilh was recruited in November 2015 on the MILVARSUNRES contract with a PROMOSOL financing. Her project is to participate in maintaining the variability of Plasmopara halstedii isolates, to identify molecular markers of pathotypes and to map new Resistance genes to Downy Mildew in Sunflower.
Luis Buendia, Master student 2 (2014-2015)
Dr Quentin Gascuel, Master 2 (2010-2011) et doctorant (2011-2014)
- PROMOSOL MilVarSunRes project : 2015-2018.MilVarSunRes: Maintaining the Variability of isolates of Plasmopara halstedii, identification of molecular markers of P. halstedii pathotypes and mapping of new Sunflower Resistances to downy Mildew.The PROMOSOL association (Association for the Promotion of selecting oilseeds) brings together representatives of the oilseeds sector, Terres Innovia (formerly CETIOM), seed companies and provides research contract with INRA. The MilVarSunRes project coordinated by L. Godiard includes three complementary axes aiming at: (i) the maintaining of the variability of Plasmopara halstedii isolates, (ii) the characterization of a complete set of effector genes as markers of pathotypes and (iii) the mapping of new broad spectrum sunflower resistances to downy mildew, previously identified by the sunflower geneticist Dr Felicity Vear (INRA Clermont-Ferrand).
- ANR EFFECTOORES project, 2014-2017:Exploitation of the knowledge on Oomycete effectors to drive the discovery of durable disease resistance in cultivated plants.This project proposes to use the most conserved genes of effector repertoires of three oomycetes Phytophthora infestans, Plasmopara viticola et Plasmopara halstedii causing disease in crops (tomato, grapevine and sunflower respectively) to accelerate the identification, the functional characterization and the cloning of broad spectrum disease resistance genes, potentially more sustainable. It includes 5 INRA laboratories and a Scottish team; L. Godiard is the scientific leader for the LIPM.