Project description:Mycorrhiza helper bacteria (MHB) promote the formation of ectomycorrhizae between tree roots and ectomycorrhizal fungi. Despite the high relevance of MHB for forestry and for sustainable tree production in tree nurseries, little is known about the properties of the bacteria that contribute to their helper abilities. The MHB strain Pseudomonas fluorescens BBc6R8 is used as a model to study the mechanisms of the helper effect. We took advantage of new technologies to obtain, for the first time, the whole genome sequence of an MHB. Analyses reveal an important plasticity of the genome with numerous functions acquired by horizontal gene tranfer. Genome mining was combined with transcriptomic and mutagenesis approaches to reveal molecular determinants of the helper effect. The data suggest that the production of helper molecules is likely to be constitutive in vitro. The helper effect appears to be pleiotropic and to rely, for a substantial part, on trophic interactions. Despite its helper abilities, the bacterium is also able in specific conditions to outcompete ectomycorrhizal fungi and inhibit their growth. We conclude that the helper bacterium possess a broad range of properties whose expression depending on the biotic and abiotic conditions can result in either a beneficial, neutral or antagonistic interaction between the plant, the ectomycorrhizal fungus and the bacterium.
Project description:Mycorrhiza helper bacteria (MHB) promote the formation of ectomycorrhizae between tree roots and ectomycorrhizal fungi. Despite the high relevance of MHB for forestry and for sustainable tree production in tree nurseries, little is known about the properties of the bacteria that contribute to their helper abilities. The MHB strain Pseudomonas fluorescens BBc6R8 is used as a model to study the mechanisms of the helper effect. We took advantage of new technologies to obtain, for the first time, the whole genome sequence of an MHB. Analyses reveal an important plasticity of the genome with numerous functions acquired by horizontal gene tranfer. Genome mining was combined with transcriptomic and mutagenesis approaches to reveal molecular determinants of the helper effect. The data suggest that the production of helper molecules is likely to be constitutive in vitro. The helper effect appears to be pleiotropic and to rely, for a substantial part, on trophic interactions. Despite its helper abilities, the bacterium is also able in specific conditions to outcompete ectomycorrhizal fungi and inhibit their growth. We conclude that the helper bacterium possess a broad range of properties whose expression depending on the biotic and abiotic conditions can result in either a beneficial, neutral or antagonistic interaction between the plant, the ectomycorrhizal fungus and the bacterium. The study was performed along a kinetic with three sampling times: before contact between the bacterial colonies and the fungus (14 days after inoculation), at the time of contact (16 days after inoculation) and after an extended period of contact (21 days). For each time, three independent replicates were performed. A control treatment without the fungus was performed in triplicate and sampled at 14 days.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and the strain Pseudomonas fluorescens Pf29Arp during their interactions in vitro.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and of two beneficial, and neutral soil bacteria during their interactions in vitro.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and the strain Pseudomonas fluorescens Pf29Arp during their interactions in vitro. We performed six hybridizations (shotgun DNA microarray) with samples derived from Pseudomonas fluorescens Pf29Arp cultivated alone or with Laccaria bicolor S238N in vitro (3 control biological replicates and 3 biological replicates with L. bicolor)
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and of two beneficial, and neutral soil bacteria during their interactions in vitro. We performed nine hybridizations (macroarray) with samples derived from Laccaria bicolor cultivated alone (3 biological replicates), with P. fluorescens BBc6R8 (3 biological replicates) and with Pf29Arp (3 biological replicates)
Project description:Illumina HiSeq technology was used to generate mRNA profiles from Suillus luteus ectomycorrhizal roots compared to free-living mycelium . Mycorrhizal roots were harvested after 40 days, pooled and used for RNA extraction. Reads of 2X100bp were generated and aligned to Suillus luteus (http://genome.jgi-psf.org/Suilu1/Suilu1.home.html) using CLC Genomics Workbench 6. mRNA profiles from Suillus luteus ectomycorrhizal roots and free-living mycelium were generated by paired-end (2x100bp) Illumina HiSeq2000 sequencing. Two biological replicates were sequenced for mycorrhizal and mycelium samples.
Project description:Illumina HiSeq technology was used to generate mRNA profiles from Paxillus involutus ectomycorrhizal roots compared to mycelium patches . Mycorrhizal roots were harvested after 4 weeks, pooled and used for RNA extraction. Reads of 2X100bp were generated and aligned to Paxillus involutus (http://genome.jgi-psf.org/Paxin1/Paxin1.home.html) using CLC Genomics Workbench 6. mRNA profiles from Paxillus involutus ectomycorrhizal roots and mycelium patches were generated by paired-end (2x100bp) Illumina HiSeq2000 sequencing. Two biological replicates were sequenced for mycorrhizal and mycelium samples.
Project description:Illumina HiSeq technology was used to generate mRNA profiles from Piloderma croceum ectomycorrhizal roots compared to free-living mycelium . Mycorrhizal roots were harvested after 8 weeks, pooled and used for RNA extraction. Reads of 2X100bp were generated and aligned to Piloderma croceum (http://genome.jgi-psf.org/Pilcr1/Pilcr1.home.html) using CLC Genomics Workbench 6. mRNA profiles from Piloderma croceum ectomycorrhizal roots and free-living mycelium were generated by paired-end (2x100bp) Illumina HiSeq2000 sequencing. Three biological replicates were sequenced for mycorrhizal and mycelium samples.
