| Doctorant : |
Lisa MARTINEZ
|
| Directeur de thèse : |
Philippe SIMIER ,
Professeur Université |
| Encadrant : |
Lucie POULIN ,
Maître de conférences Université |
| Encadrant : | Christophe JESTIN, Ingénieur chargé d’études, Terres Inovia (INRAe - Centre Bretagne Normandie) |
| Financement : |
|
| Date de la soutenance : |
vendredi 10 mars 2023, 14h00 |
| Modalité : |
|
| Jury : |
- Président de jury : Florence WISNIEWSKI-DYÉ Professeure, Université Claude Bernard Lyon 1
- Rapporteur : Florence WISNIEWSKI-DYÉ Professeure, Université Claude Bernard Lyon 1
- Rapporteur : Jean-Benoît MOREL, directeur de recherche, INRAe Montpellier
- Examinateur : Stéphanie GIBOT-LECLERC Maître de Conférences, Agrosup Dijon
- Examinateur :
Philippe SIMIER ,
Professeur Université
- Directeur de thèse :
Philippe SIMIER ,
Professeur Université
- Encadrant :
Lucie POULIN ,
Maître de conférences Université
- Encadrant : Christophe JESTIN, Ingénieur chargé d’études, Terres Inovia (INRAe - Centre Bretagne Normandie)
- Invité :
Lucie POULIN ,
Maître de conférences Université
|
L’augmentation du parasitisme de l’orobanche rameuse, plante parasite racinaire obligatoire du colza d’hiver dans l’ouest français, couplée à sa diminution localisée sur quelques parcelles au sein du même contexte pédoclimatique, suggèrent que l’interaction entre les deux plantes est multifactorielle et doit être mieux appréhendée. A partir de l’étude de sols présentant deux niveaux d’infestations, dits compatibles et suppressifs, ces travaux soutiennent l’hypothèse d’une interaction tripartite avec le microbiote du sol. Dans un premier temps, ce dernier contribuerait à amplifier le signal moléculaire rhizosphérique, nécessaire pour la reconnaissance du colza par l’orobanche. Plus précisément, des activités enzymatiques spécifiques au métabolome du colza (myrosinases) permettant l’induction de la germination de l’orobanche, ainsi que la production de molécules signales initiant la formation du parasitisme, ont été détectées et fonctionnellement validées chez des bactéries et champignons des deux types de sol. Dans un second temps, le suivi de l’évolution du microbiote du sol et de la rhizosphère durant le parasitisme a permis de valider les observations de terrains sur les sols suppressifs et surtout de mettre en évidence des microorganismes ciblant spécifiquement l’orobanche. Plus précisément, certaines associations microbiennes ont été positivement corrélées à la réduction de l’infestation et à l’apparition de symptômes nécrotiques. Finalement, deux candidats fongiques ont été proposés à partir de la mise au point d’une méthode de détection de nécroses par analyse d’image. Cette étude a permis d’approfondir la communication allélopathique entre les plantes hôtes, les plantes parasites et leurs microbiotes associés.
Publications
2022
Martinez, Lisa; Pouvreau, Jean-Bernard; Montiel, Gregory; Jestin, Christophe; Delavault, Philippe; Simier, Philippe; Poulin, Lucie
Soil microbiota promotes early developmental stages of Phelipanche ramosa L. Pomel during plant parasitism on Brassica napus L. Article de journal
Dans: Plant and Soil, vol. 483, p. 667–691 , 2022.
@article{martinez2022soil,
title = {Soil microbiota promotes early developmental stages of Phelipanche ramosa L. Pomel during plant parasitism on Brassica napus L.},
author = {Lisa Martinez and Jean-Bernard Pouvreau and Gregory Montiel and Christophe Jestin and Philippe Delavault and Philippe Simier and Lucie Poulin},
doi = {https://doi.org/10.1007/s11104-022-05822-6},
year = {2022},
date = {2022-12-08},
urldate = {2022-12-08},
journal = {Plant and Soil},
volume = {483},
pages = {667–691 },
publisher = {Springer},
abstract = {Purpose
The root holoparasitic plant Phelipanche ramosa has become a major constraint for rapeseed cultivation in western France for the last decades and its control remains challenging. To date, few studies have considered soil microbiota as a third partner of the parasitic plant-plant interaction. Therefore, we here addressed the question of how soil microbiota interferes with host-derived signal metabolites required for host plant recognition by the parasitic plant.
Methods
Using a branched broomrape infested soil (genetic group 1) from a rapeseed field, we first provided soil physicochemical and microbiological descriptions by metabarcoding, followed by P. ramosa seed germination and prehaustorium formation bioassays, and by in vitro co-cultivation with Brassica napus.
Results
Co-cultivation in presence of soil microorganisms promoted parasitic plant seed germination and attachments to host’s roots. Seed germination assays showed that only the combination of gluconasturtiin (main rapeseed glucosinolate) with soil extracts stimulated broomrape germination. This suggests a microbial conversion of gluconasturtiin into germination stimulants via soil microbial myrosinase enzymes. Furthermore, soil bacteria Arthrobacter, Ralstonia, Actinobacterium, Proteobacterium spp. and fungus Penicillium spp. were isolated and screened for myrosinase activity. Pre-germinated seeds treated with soil extracts or differentially filtrated soil extracts also promoted the formation of P. ramosa prehaustorium and led to more parasitic attachments on rapeseed roots in co-cultivation assays. This thus suggests that this enhancement of parasitic attachments could also be partly attributed to soil microbial production of haustorium inducing factors.
Conclusion
Soil microbiota influences B. napus - P. ramosa interaction by altering direct and indirect recognition signals.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose
The root holoparasitic plant Phelipanche ramosa has become a major constraint for rapeseed cultivation in western France for the last decades and its control remains challenging. To date, few studies have considered soil microbiota as a third partner of the parasitic plant-plant interaction. Therefore, we here addressed the question of how soil microbiota interferes with host-derived signal metabolites required for host plant recognition by the parasitic plant.
Methods
Using a branched broomrape infested soil (genetic group 1) from a rapeseed field, we first provided soil physicochemical and microbiological descriptions by metabarcoding, followed by P. ramosa seed germination and prehaustorium formation bioassays, and by in vitro co-cultivation with Brassica napus.
Results
Co-cultivation in presence of soil microorganisms promoted parasitic plant seed germination and attachments to host’s roots. Seed germination assays showed that only the combination of gluconasturtiin (main rapeseed glucosinolate) with soil extracts stimulated broomrape germination. This suggests a microbial conversion of gluconasturtiin into germination stimulants via soil microbial myrosinase enzymes. Furthermore, soil bacteria Arthrobacter, Ralstonia, Actinobacterium, Proteobacterium spp. and fungus Penicillium spp. were isolated and screened for myrosinase activity. Pre-germinated seeds treated with soil extracts or differentially filtrated soil extracts also promoted the formation of P. ramosa prehaustorium and led to more parasitic attachments on rapeseed roots in co-cultivation assays. This thus suggests that this enhancement of parasitic attachments could also be partly attributed to soil microbial production of haustorium inducing factors.
Conclusion
Soil microbiota influences B. napus - P. ramosa interaction by altering direct and indirect recognition signals.
Lien
