Project description:Arbuscular mycorrhizal (AM) symbiosis that associates roots of most land plants with soilborne fungi (Glomeromycota), is characterized by reciprocal nutritional benefits. Fungal colonization of plant roots induces massive changes in cortical cells where the fungus differentiates an arbuscule, which drives proliferation of the plasma membrane, and the de novo synthesis of the periarbuscular membrane. Despite the recognized importance of membrane proteins in sustaining AM symbiosis, the root microsomal proteome elicited upon mycorrhiza still remains to be explored. In this study, we first examined the qualitative composition of the root membrane proteome of Medicago truncatula after microsome enrichment and subsequent in depth analysis by GeLC-MS/MS. The results obtained highlighted the identification of 1226 root membrane protein candidates whose cellular and functional classifications predispose plastids and protein synthesis as prevalent organelle and function, respectively. Changes at the protein abundance level between the membrane proteomes of mycorrhizal and nonmycorrhizal roots were further monitored by spectral counting, which retrieved a total of 97 proteins that displayed a differential accumulation upon AM symbiosis. Besides the canonical markers of the periarbuscular membrane, new candidates supporting the importance of membrane trafficking events during mycorrhiza establishment/functioning were identified, including flotillin-like proteins.
Project description:This study characterizes the transcriptomic alterations of P. tremula x P. alba at three weeks after inoculation with the ectomycorrhizal fungus Laccaria bicolor. We performed 6 hybridizations (NimbleGen) with samples derived from Populus tremula x P. alba control roots and mycorrhizal root tips. Samples were taken after 3 weeks of interaction (three biological replicates). All samples were labeled with Cy3.
Project description:Laccaria bicolor transcript profiles of different tissues and mycorrhizal root tips from different host trees were analyzed. The array probes were designed from gene models taken from the Joint Genome Institute (JGI, department of energy) Laccaria bicolor genome sequence version 1. One goal was to compare gene expression profiles from ectomycorrhizal root tips with different host plants. Overall design: We performed 12 hybridizations (Roche-NimbleGen) with samples derived from Laccaria bicolor free-living mycelium and from Populus trichocarpa, P. deltoides and douglas fir ECM.
Project description:Arbuscular mycorrhizal (AM) associations enhance the phosphorous and nitrogen nutrition of host plants, but little is known about their role in potassium (K+) nutrition. Medicago truncatula plants were co-cultured with the AM fungus Rhizophagus irregularis under high and low K+ regimes for six weeks. We determined how K+ deprivation affects plant development, mineral acquisition, and how these negative effects are tempered by the AM colonization. The transcriptional response of AM roots under K+ deficiency was analyzed by whole genome RNA-seq. K+ deprivation decreased root biomass, external K+ uptake, and modulated oxidative stress gene expression in M. truncatula roots. AM colonization induced specific transcriptional responses to K+ deprivation that seem to temper these negative effects. A gene network analysis revealed putative key regulators of these responses. This study confirmed that AM associations provide some tolerance to K+ deprivation to host plants, revealed that AM symbiosis modulates the expression of specific root genes to cope with this nutrient stress, and identified putative regulators participating in these tolerance mechanisms. Overall design: Medicago truncatula were inoculated or not with the arbuscular mycorrhizal fungus Rhizophagus irregularis and watered with a high (3.75 mM) or low (0.05 mM) potassium solution for six weeks. RNAs from three to four biological replicates composed of four plants each were sequenced.
Project description:This study characterizes the transcriptomic alterations of P. trichocarpa during interaction with the ectomycorrhizal fungus Laccaria bicolor S238N. Four time-points were analyzed, two weeks, four weeks , six weeks and twelve weeks after inoculation. Overall design: We performed 32 hybridizations (NimbleGen) with samples derived from Populus trichocarpa control roots and P.trichocarpa mycorrhizal root tips. Samples were taken after 2,4,6 and 12 weeks of interaction (four biological replicates). All samples were labeled with Cy3.