@article{Martinez2024,

title = {Comparative Analysis of Two Neighboring Conducive and Suppressive Soils Toward Plant Parasitism Caused by \textit{Phelipanche ramosa} on \textit{Brassica napus}},

author = {Lisa Martinez and Jean-Bernard Pouvreau and Christophe Jestin and Gregory Montiel and Antoine Gravot and Solenne Berardocco and Nathalie Marnet and Alain Bouchereau and Erwan Delage and Philippe Simier and Lucie Poulin},

doi = {10.1094/pbiomes-12-23-0140-r},

issn = {2471-2906},

year  = {2024},

date = {2024-11-00},

urldate = {2024-11-00},

journal = {Phytobiomes Journal},

volume = {8},

number = {4},

pages = {425--445},

publisher = {Scientific Societies},

abstract = {<jats:p> In Western France, rapeseed ( Brassica napus) cultivation faces substantial yield losses due to the root holoparasitic plant Phelipanche ramosa. However, recent observations have shown a reduction in parasitism within previously heavily infested fields. This study investigates two neighboring rapeseed soils with distinct levels of parasitic infestation, considered suppressive and conducive. Using a cocultivation system of Brassica napus and P. ramosa, we comprehensively examined rhizosphere exudates, parasitic plant attachment, and rhizosphere soil microbiota. Our findings revealed that the suppressive soil effectively reduced parasitism by impeding broomrape attachment and development, as well as inducing necrosis of tubercles. This suppressive effect was specific to postattachment stages, leaving germination and haustoriogenesis preattachment stages unaffected. Analysis of microbial structures suggested that the suppression of parasitism is predominantly of fungal rather than bacterial origin. Correlation network analyses identified three groups of amplicon sequence variants (ASVs) associated with suppression. Notably, seven ASVs were inversely correlated with parasitic attachments, and only one ASV, identified as Berkeleyomyces, a necrotrophic fungus responsible for black root rot, was positively correlated with necrosis and was more abundant in the suppressive soil. This study demonstrates the contrasting parasitic plant development on two physicochemically similar soils, highlighting the central role of fungal dynamics in the rhizosphere. These results provide valuable insights into the mechanisms underlying soil-mediated suppression of P. ramosa, offering potential strategies for mitigating the impact of this root holoparasite on rapeseed yields in the region. </jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37640279,

title = {Vitislactone, a non-canonical strigolactone exudated by grapevine rootstocks in response to nitrogen starvation},

author = {Vincent Lailheugue and Isabelle Merlin and Stéphanie Boutet and François Perreau and Jean-Bernard Pouvreau and Sabine Delgrange and Paul-Henri Ducrot and Betty Cottyn-Boitte and Gregory Mouille and Virginie Lauvergeat},

url = { hal-04247159v1 },

doi = {10.1016/j.phytochem.2023.113837},

issn = {1873-3700},

year  = {2023},

date = {2023-08-01},

urldate = {2023-08-01},

journal = {Phytochemistry},

volume = {215},

pages = {113837},

abstract = {Strigolactones are compounds produced by plant roots in response to nutrient deficiency, acting both as local and systemic signals to control development and nutrition. Strigolactones are exuded in the rhizosphere to positively influence interactions with beneficial microbes. LC-MS/MS analysis shows that two genetically distinct grapevine rootstocks exudate one or two non-canonical strigolactones when subjected to low nitrogen conditions. Gene expression profiles and orobanche seed germination assays confirm that the biosynthesis and exudation of non-canonical compounds is the preferred pathway. The first compound, corresponding to heliolactone or 6-epi-heliolactone, is only exuded by the rootstock showing lower shoot branching and a higher level of mycorrhization with arbuscular mycorrhizal fungi. The structure of the second compound exuded by both rootstocks was identified by NMR and LC-MS/MS analysis. It is a non-canonical strigolactone, which has never been identified in another species. This first identification of a natural compound with the potential to stimulate beneficial root-microbe interactions in grapevines opens new perspectives in viticulture.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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},

url = {https://nantes-universite.hal.science/hal-04370677v1 },

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}

}

@article{pmid35776904,

title = {Noncanonical Strigolactone Analogues Highlight Selectivity for Stimulating Germination in Two  Populations},

author = {Suzanne Daignan Fornier and Alexandre de Saint Germain and Pascal Retailleau and Jean-Paul Pillot and Quentin Taulera and Lucile Andna and Laurence Miesch and Soizic Rochange and Jean-Bernard Pouvreau and François-Didier Boyer},

url = {hal-03712428v1 },

doi = {10.1021/acs.jnatprod.2c00282},

issn = {1520-6025},

year  = {2022},

date = {2022-08-01},

urldate = {2022-08-01},

journal = {J Nat Prod},

volume = {85},

number = {8},

pages = {1976--1992},

abstract = {Strigolactones (SLs) are plant hormones exuded in the rhizosphere with a signaling role for the development of arbuscular mycorrhizal (AM) fungi and as stimulants of seed germination of the parasitic weeds , , and , the most threatening weeds of major crops worldwide.  is present mainly on rape, hemp, and tobacco in France.  2a preferentially attacks hemp, while  1 attacks rapeseed. The recently isolated cannalactone () from hemp root exudates has been characterized as a noncanonical SL that selectively stimulates the germination of  2a seeds in comparison with  1. In the present work, (-)-solanacol (), a canonical orobanchol-type SL exuded by tobacco and tomato, was established to possess a remarkable selective germination stimulant activity for  2a seeds. Two cannalactone analogues, named (±)-SdL19 and (±)-SdL118, have been synthesized. They have an unsaturated acyclic carbon chain with a tertiary hydroxy group and a methyl or a cyclopropyl group instead of a cyclohexane A-ring, respectively. (±)-SdL analogues are able to selectively stimulate  2a, revealing that these minimal structural elements are key for this selective bioactivity. In addition, (±)-SdL19 is able to inhibit shoot branching in  and  and induces hyphal branching in the AM fungus , like SLs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36340383,

title = {Wild  species: A reservoir of resistance genes for sustainable pyramidal resistance to broomrape in sunflower},

author = {Mireille Chabaud and Marie-Christine Auriac and Marie-Claude Boniface and Sabine Delgrange and Tifaine Folletti and Marie-Françoise Jardinaud and Alexandra Legendre and Begoña Pérez-Vich and Jean-Bernard Pouvreau and Leonardo Velasco and Philippe Delavault and Stéphane Muños},

url = {hal-03877893v1 },

doi = {10.3389/fpls.2022.1038684},

issn = {1664-462X},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Front Plant Sci},

volume = {13},

pages = {1038684},

abstract = { Wall., sunflower broomrape, is one of the major pests for the sunflower crop. Breeding for resistant varieties in sunflower has been the most efficient method to control this parasitic weed. However, more virulent broomrape populations continuously emerge by overcoming genetic resistance. It is thus essential to identify new broomrape resistances acting at various stages of the interaction and combine them to improve resistance durability. In this study, 71 wild sunflowers and wild relatives accessions from 16  species were screened in pots for their resistance to broomrape at the late emergence stage. From this initial screen, 18 accessions from 9 species showing resistance, were phenotyped at early stages of the interaction: the induction of broomrape seed germination by sunflower root exudates, the attachment to the host root and the development of tubercles in rhizotron assays. We showed that wild  accessions are an important source of resistance to the most virulent broomrape races, affecting various stages of the interaction: the inability to induce broomrape seed germination, the development of incompatible attachments or necrotic tubercles, and the arrest of emerged structure growth. Cytological studies of incompatible attachments showed that several cellular mechanisms were shared among resistant  species.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34498760,

title = {Strigolactones (SLs) modulate the plastochron by regulating KLUH (KLU) transcript abundance in Arabidopsis},

author = {Florent Cornet and Jean-Paul Pillot and Philippe Le Bris and Jean-Bernard Pouvreau and Nicolas Arnaud and Alexandre de Saint Germain and Catherine Rameau},

doi = {10.1111/nph.17725},

issn = {1469-8137},

year  = {2021},

date = {2021-12-01},

urldate = {2021-12-01},

journal = {New Phytol},

volume = {232},

number = {5},

pages = {1909--1916},

abstract = {The timing of leaf emergence at the shoot apical meristem, or plastochron, is highly regulated in plants. Among the genes known to regulate the plastochron in Arabidopsis (Arabidopsis thaliana), KLUH (KLU), orthologous to the rice (Oryza sativa) PLASTOCHRON1, encodes the cytochrome P450 CYP78A5, and is thought to act through generation of a still unknown mobile signal. As klu mutants display not only a short plastochron but also a branching phenotype reminiscent of strigolactone (SL) mutants, we investigated whether KLU/CYP78A5 is involved in SL biosynthesis. We combined a genetic approach, a parasitic plant seed germination bioassay to test klu root exudates, and analysis of transcript abundances of SL-biosynthesis genes in the Arabidopsis klu mutants. We demonstrate that KLU is not involved in the SL-biosynthesis pathway. Moreover, this work allowed us to uncover a new role for SL during Arabidopsis development in modulating plastochron via a KLU-dependent pathway. Globally our data reveal that KLU is required for plastochron-specific SL responses, a first indication of crosstalk between SL and the KLU-derived signal.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN13,

title = {A Phelipanche ramosa KAI2 protein perceives strigolactones and isothiocyanates enzymatically},

author = {Alexandre Saint Germain and Anse Jacobs and Guillaume Brun and Jean-Bernard Pouvreau and Lukas Braem and David Cornu and Guillaume Clavé and Emmanuelle Baudu and Vincent Steinmetz and Vincent Servajean and Susann Wicke and Kris Gevaert and Philippe Simier and Sophie Goormachtig and Philippe Delavault and François-Didier Boyer},

url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8553955/pdf/main.pdf},

doi = {10.1016/j.xplc.2021.100166},

issn = {2590-3462},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Plant Commun},

volume = {2},

number = {5},

pages = {100166},

abstract = {Phelipanche ramosa is an obligate root-parasitic weed that threatens major crops in central Europe. In order to germinate, it must perceive various structurally divergent host-exuded signals, including isothiocyanates (ITCs) and strigolactones (SLs). However, the receptors involved are still uncharacterized. Here, we identify five putative SL receptors in P. ramosa and show that PrKAI2d3 is involved in the stimulation of seed germination. We demonstrate the high plasticity of PrKAI2d3, which allows it to interact with different chemicals, including ITCs. The SL perception mechanism of PrKAI2d3 is similar to that of endogenous SLs in non-parasitic plants. We provide evidence that PrKAI2d3 enzymatic activity confers hypersensitivity to SLs. Additionally, we demonstrate that methylbutenolide-OH binds PrKAI2d3 and stimulates P. ramosa germination with bioactivity comparable to that of ITCs. This study demonstrates that P. ramosa has extended its signal perception system during evolution, a fact that should be considered for the development of specific and efficient biocontrol methods.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34028679b,

title = {Strigolactone-Like Bioactivity via Parasitic Plant Germination Bioassay},

author = {Jean-Bernard Pouvreau and Lucie Poulin and Sarah Huet and Philippe Delavault},

doi = {10.1007/978-1-0716-1429-7_6},

issn = {1940-6029},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Methods Mol Biol},

volume = {2309},

pages = {59--73},

abstract = {Strigolactones are a class of plant hormones involved in shoot branching, growth of symbiotic arbuscular mycorrhizal fungi, and germination of parasitic plant seeds. Assaying new molecules or compound exhibiting strigolactone-like activities is therefore important but unfortunately time-consuming and hard to implement because of the extremely low concentrations at which they are active. Seeds of parasite plants are natural integrator of these hormones since they can perceive molecule concentrations in the picomolar to nanomolar range stimulating their germination. Here we describe a simple and inexpensive method to evaluate the activity of these molecules by scoring the germination of parasitic plant seeds upon treatment with these molecules. Up to four molecules can be assayed from a single 96-well plate by this method. A comparison of SL-like bioactivities between molecules is done by determining the EC50 and the maximum percentage of germination.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN27,

title = {The Physcomitrium (Physcomitrella) patens PpKAI2L receptors for strigolactones and related compounds function via MAX2-dependent and -independent pathways},

author = {Mauricio Lopez-Obando and Ambre Guillory and François-Didier Boyer and David Cornu and Beate Hoffmann and Philippe Le Bris and Jean-Bernard Pouvreau and Philippe Delavault and Catherine Rameau and Alexandre Saint Germain and Sandrine Bonhomme},

url = {https://academic.oup.com/plcell/article-abstract/33/11/3487/6359828?redirectedFrom=fulltext},

doi = {10.1093/plcell/koab217},

issn = {1040-4651 (Print) 1040-4651},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Plant Cell},

volume = {33},

number = {11},

pages = {3487-3512},

abstract = {In angiosperms, the α/β hydrolase DWARF14 (D14), along with the F-box protein MORE AXILLARY GROWTH2 (MAX2), perceives strigolactones (SL) to regulate developmental processes. The key SL biosynthetic enzyme CAROTENOID CLEAVAGE DIOXYGENASE8 (CCD8) is present in the moss Physcomitrium patens, and PpCCD8-derived compounds regulate moss extension. The PpMAX2 homolog is not involved in the SL response, but 13 PpKAI2LIKE (PpKAI2L) genes homologous to the D14 ancestral paralog KARRIKIN INSENSITIVE2 (KAI2) encode candidate SL receptors. In Arabidopsis thaliana, AtKAI2 perceives karrikins and the elusive endogenous KAI2-Ligand (KL). Here, germination assays of the parasitic plant Phelipanche ramosa suggested that PpCCD8-derived compounds are likely noncanonical SLs. (+)-GR24 SL analog is a good mimic for PpCCD8-derived compounds in P. patens, while the effects of its enantiomer (-)-GR24, a KL mimic in angiosperms, are minimal. Interaction and binding assays of seven PpKAI2L proteins pointed to the stereoselectivity toward (-)-GR24 for a single clade of PpKAI2L (eu-KAI2). Enzyme assays highlighted the peculiar behavior of PpKAI2L-H. Phenotypic characterization of Ppkai2l mutants showed that eu-KAI2 genes are not involved in the perception of PpCCD8-derived compounds but act in a PpMAX2-dependent pathway. In contrast, mutations in PpKAI2L-G, and -J genes abolished the response to the (+)-GR24 enantiomer, suggesting that PpKAI2L-G, and -J proteins are receptors for moss SLs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid32765559,

title = {Populations of the Parasitic Plant  Influence Their Seed Microbiota},

author = {Sarah Huet and Jean-Bernard Pouvreau and Erwan Delage and Sabine Delgrange and Coralie Marais and Muriel Bahut and Philippe Delavault and Philippe Simier and Lucie Poulin},

doi = {10.3389/fpls.2020.01075},

issn = {1664-462X},

year  = {2020},

date = {2020-01-01},

urldate = {2020-01-01},

journal = {Front Plant Sci},

volume = {11},

pages = {1075},

abstract = {Seeds of the parasitic weed  are well adapted to their hosts because they germinate and form haustorial structures to connect to roots in response to diverse host-derived molecular signals.  presents different genetic groups that are preferentially adapted to certain hosts. Since there are indications that microbes play a role in the interaction especially in the early stages of the interaction, we studied the microbial diversity harbored by the parasitic seeds with respect to their host and genetic group. Twenty-six seed lots from seven cropping plots of three different hosts-oilseed rape, tobacco, and hemp-in the west of France were characterized for their bacterial and fungal communities using 16S rRNA gene and ITS (Internal transcribed spacer) sequences, respectively. First seeds were characterized genetically using twenty microsatellite markers and phenotyped for their sensibility to various germination stimulants including strigolactones and isothiocyanates. This led to the distinction of three  groups that corresponded to their host of origin. The observed seed diversity was correlated to the host specialization and germination stimulant sensitivity within  species. Microbial communities were both clustered by host and plot of origin. The seed core microbiota was composed of seventeen species that were also retrieved from soil and was in lower abundances for bacteria and similar abundances for fungi compared to seeds. The host-related core microbiota of parasitic seeds was limited and presumably well adapted to the interaction with its hosts. Two microbial candidates of  species and  were especially identified in seeds from oilseed rape plots, suggesting their involvement in host recognition and specialization as well as seed fitness for  by improving the production of isothiocyanates from glucosinolates in the rhizosphere of oilseed rape.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid31499274,

title = {Contalactone, a contaminant formed during chemical synthesis of the strigolactone reference GR24 is also a strigolactone mimic},

author = {Alexandre de Saint Germain and Pascal Retailleau and Stéphanie Norsikian and Vincent Servajean and Franck Pelissier and Vincent Steinmetz and Jean-Paul Pillot and Soizic Rochange and Jean-Bernard Pouvreau and François-Didier Boyer},

url = {hal-03010596v1 },

doi = {10.1016/j.phytochem.2019.112112},

issn = {1873-3700},

year  = {2019},

date = {2019-12-01},

urldate = {2019-12-01},

journal = {Phytochemistry},

volume = {168},

pages = {112112},

abstract = {Strigolactone (SL) plant hormones control plant architecture and are key players in both symbiotic and parasitic interactions. GR24, a synthetic SL analog, is the worldwide reference compound used in all bioassays for investigating the role of SLs in plant development and in rhizospheric interactions. In 2012, the first characterization of the SL receptor reported the detection of an unknown compound after incubation of GR24 samples with the SL receptor. We reveal here the origin of this compound (P270), which comes from a by-product formed during GR24 chemical synthesis. We present the identification of this by-product, named contalactone. A proposed chemical pathway for its formation is provided as well as an evaluation of its bioactivity on pea, Arabidopsis, root parasitic plant seeds and AM fungi, characterizing it as a SL mimic. Quality of GR24 samples can be easily checked by carrying out microscale hydrolysis in a basic aqueous medium to easily detect P270 as indicator of the presence of the contalactone impurity. In all cases, before being used for bioassays, GR24 must be careful purified by preparative HPLC.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN7,

title = {CYP707As are effectors of karrikin and strigolactone signalling pathways in Arabidopsis thaliana and parasitic plants},

author = {Guillaume Brun and Séverine Thoiron and Lukas Braem and Jean-Bernard Pouvreau and Grégory Montiel and Marc-Marie Lechat and Philippe Simier and Kris Gevaert and Sophie Goormachtig and Philippe Delavault},

url = {https://onlinelibrary.wiley.com/doi/10.1111/pce.13594},

doi = {10.1111/pce.13594},

issn = {0140-7791},

year  = {2019},

date = {2019-01-01},

urldate = {2019-01-01},

journal = {Plant Cell Environ},

volume = {42},

number = {9},

pages = {2612-2626},

abstract = {Karrikins stimulate Arabidopsis thaliana germination, whereas parasitic weeds of the Orobanchaceae family have evolved to respond to host-exuded compounds such as strigolactones, dehydrocostus lactone, and 2-phenylethyl isothiocyanate. In Phelipanche ramosa, strigolactone-induced germination was shown to require one of the CYP707A proteins involved in abscisic acid catabolism. Here, germination and gene expression were analysed to investigate the role of CYP707As in germination of both parasitic plants and Arabidopsis upon perception of germination stimulants, after using pharmacological inhibitors and Arabidopsis mutants disrupting germination signals. CYP707A genes were up-regulated upon treatment with effective germination stimulants in both parasitic plants and Arabidopsis. Obligate parasitic plants exhibited both intensified up-regulation of CYP707A genes and increased sensitivity to the CYP707A inhibitor abscinazole-E2B, whereas Arabidopsis cyp707a mutants still positively responded to germination stimulation. In Arabidopsis, CYP707A regulation required the canonical karrikin signalling pathway KAI2/MAX2/SMAX1 and the transcription factor WRKY33. Finally, CYP707As and WRKY33 also modulated Arabidopsis root architecture in response to the synthetic strigolactone rac-GR24, and wrky33-1 exhibited a shoot hyperbranched phenotype. This study suggests that the lack of host-independent germination in obligate parasites is associated with an exacerbated CYP707A induction and that CYP707As and WRKY33 are new players involved in a variety of strigolactone/karrikin responses.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29860350,

title = {Potential contribution of strigolactones in regulating scion growth and branching in grafted grapevine in response to nitrogen availability},

author = {Noé Cochetel and Eloïse Météier and Isabelle Merlin and Cyril Hévin and Jean-Bernard Pouvreau and Pierre Coutos-Thévenot and Michel Hernould and Philippe Vivin and Sarah Jane Cookson and Nathalie Ollat and Virginie Lauvergeat},

doi = {10.1093/jxb/ery206},

issn = {1460-2431},

year  = {2018},

date = {2018-07-01},

urldate = {2018-07-01},

journal = {J Exp Bot},

volume = {69},

number = {16},

pages = {4099--4112},

abstract = {In grafted plants, rootstocks assure the mineral nutrition of the scion and modify its development. In this study, we show that two grapevine rootstock genotypes have different shoot branching architectures when cultivated as cuttings and that this trait is transmitted to the scion when grafted. Shoot branching plasticity in response to nitrogen supply was also studied. As strigolactones are known to have a role in the regulation of shoot development in response to nutrient availability, their involvement in the control of scion architecture by the rootstock was investigated. Functional characterization of putative grapevine strigolactone biosynthetic genes in Arabidopsis mutants or grapevine cell suspensions showed similar functions to those of Arabidopsis. Both rootstocks produced strigolactone-like compounds; the quantity produced in response to nitrogen treatments differed between the two rootstock genotypes and correlated with the expression of putative strigolactone biosynthetic genes. Exudation of strigolactone-like compounds by both rootstocks was closely related to the developmental pattern of the scion in grafted plants. These results suggest that differential regulation of strigolactone biosynthesis in response to nitrogen availability may contribute to the control of scion development conferred by each rootstock genotype.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN11,

title = {Haustorium initiation in the obligate parasitic plant Phelipanche ramosa involves a host-exudated cytokinin signal},

author = {Vincent Goyet and Estelle Billard and Jean-Bernard Pouvreau and Marc-Marie Lechat and Sandra Pelletier and Muriel Bahut and Fabrice Monteau and Lukas Spíchal and Philippe Delavault and Grégory Montiel and Philippe Simier},

url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853424/pdf/erx359.pdf},

doi = {10.1093/jxb/erx359},

issn = {0022-0957 (Print) 0022-0957},

year  = {2017},

date = {2017-01-01},

urldate = {2017-01-01},

journal = {J Exp Bot},

volume = {68},

number = {20},

pages = {5539-5552},

abstract = {The heterotrophic lifestyle of parasitic plants relies on the development of the haustorium, a specific infectious organ required for attachment to host roots. While haustorium development is initiated upon chemodetection of host-derived molecules in hemiparasitic plants, the induction of haustorium formation remains largely unknown in holoparasitic species such as Phelipanche ramosa. This work demonstrates that the root exudates of the host plant Brassica napus contain allelochemicals displaying haustorium-inducing activity on P. ramosa germinating seeds, which increases the parasite aggressiveness. A de novo assembled transcriptome and microarray approach with P. ramosa during early haustorium formation upon treatment with B. napus root exudates allowed the identification of differentially expressed genes involved in hormone signaling. Bioassays using exogenous cytokinins and the specific cytokinin receptor inhibitor PI-55 showed that cytokinins induced haustorium formation and increased parasite aggressiveness. Root exudates triggered the expression of cytokinin-responsive genes during early haustorium development in germinated seeds, and bio-guided UPLC-ESI(+)-/MS/MS analysis showed that these exudates contain a cytokinin with dihydrozeatin characteristics. These results suggest that cytokinins constitutively exudated from host roots play a major role in haustorium formation and aggressiveness in P. ramosa.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN22,

title = {Seed response to strigolactone is controlled by abscisic acid-independent DNA methylation in the obligate root parasitic plant, Phelipanche ramosa L. Pomel},

author = {Marc-Marie Lechat and Guillaume Brun and Grégory Montiel and Christophe Véronési and Philippe Simier and Séverine Thoiron and Jean-Bernard Pouvreau and Philippe Delavault},

url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4449535/pdf/erv119.pdf},

doi = {10.1093/jxb/erv119},

issn = {0022-0957 (Print) 0022-0957},

year  = {2015},

date = {2015-01-01},

urldate = {2015-01-01},

journal = {J Exp Bot},

volume = {66},

number = {11},

pages = {3129-40},

abstract = {Seed dormancy release of the obligate root parasitic plant, Phelipanche ramosa, requires a minimum 4-day conditioning period followed by stimulation by host-derived germination stimulants, such as strigolactones. Germination is then mediated by germination stimulant-dependent activation of PrCYP707A1, an abscisic acid catabolic gene. The molecular mechanisms occurring during the conditioning period that silence PrCYP707A1 expression and regulate germination stimulant response are almost unknown. Here, global DNA methylation quantification associated with pharmacological approaches and cytosine methylation analysis of the PrCYP707A1 promoter were used to investigate the modulation and possible role of DNA methylation during the conditioning period and in the PrCYP707A1 response to GR24, a synthetic strigolactone analogue. Active global DNA demethylation occurs during the conditioning period and is required for PrCYP707A1 activation by GR24 and for subsequent seed germination. Treatment with 5-azacytidine, a DNA-hypomethylating molecule, reduces the length of the conditioning period. Conversely, hydroxyurea, a hypermethylating agent, inhibits PrCYP707A1 expression and seed germination. Methylated DNA immunoprecipitation followed by PCR experiments and bisulfite sequencing revealed that DNA demethylation particularly impacts a 78-nucleotide sequence in the PrCYP707A1 promoter. The results here demonstrate that the DNA methylation status during the conditioning period plays a crucial role independently of abscisic acid in the regulation of P. ramosa seed germination by controlling the strigolactone-dependent expression of PrCYP707A1.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}