Project description:This SuperSeries is composed of the following subset Series: GSE33636: Gene expression data from Medicago truncatula plantlet roots treated with symbiotic lipochitooligosaccharides (LCOs). GSE33637: Gene expression data from Medicago truncatula mutant plantlet roots treated with Myc-LCOs. Refer to individual Series
Project description:Publication title: Pseudonodule formation by wild type and symbiotic mutant Medicago truncatula in response to auxin transport inhibitors This SuperSeries is composed of the SubSeries listed below.
Project description:Legumes interact with soil microbes, leading to the development of nitrogen-fixing root nodules and arbuscular mycorrhizal (AM) roots. While nodule initiation by diffusible lipochitooligosaccharide (LCO) Nod-factors of bacterial origin (Nod-LCOs) is well characterized, diffusible AM fungal signals were only recently identified as sulphated and non-sulphated LCOs (sMyc-LCOs and nsMyc-LCOs). Applying Myc-LCOs in parallel to Nod-LCOs, we used GeneChips to detail the global programme of gene expression in response to the external application of symbiotic LCOs.
Project description:This experiment constitutes an expression profiling approach to identify genes differentially regulated during the symbiotic interaction between the model legume Medicago truncatula and the nitrogen-fixing bacterium Sinorhizobium meliloti. Macro- and microarrays containing 6144 probes were generated on the basis of three cDNA libraries dedicated to the study of root symbiotic interactions. The experiment performed on wild-type and symbiotic mutant material led to the identification of genes either up- or down-regulated at different stages of the nodulation process.
Project description:Legumes interact with soil microbes, leading to the development of nitrogen-fixing root nodules and arbuscular mycorrhizal (AM) roots. While nodule initiation by diffusible lipochitooligosaccharide (LCO) Nod-factors of bacterial origin (Nod-LCOs) is well characterized, diffusible AM fungal signals were only recently identified as sulphated and non-sulphated LCOs (sMyc-LCOs and nsMyc-LCOs). Applying Myc-LCOs in parallel to Nod-LCOs, we used GeneChips to detail the global programme of gene expression in response to the external application of symbiotic LCOs. To harvest tissues for transcriptome profiling, three biological replicates consisting of 20 plantlets per treatment were selected. After 6 h of incubation in the climate chamber, 10 plantlets per batch were removed from the treatment (Myc-LCOs or Nod-LCOs) or control solutions and harvested, while the other 10 remained in the respective solutions for a total of 24 h. During harvest, one mm of the root tip of each plantlet was removed and discarded. The remaining 2 to 2.5 cm of the distal root region were cut off and directly frozen in liquid nitrogen.
Project description:Publication title: Pseudonodule formation by wild type and symbiotic mutant Medicago truncatula in response to auxin transport inhibitors This SuperSeries is composed of the following subset Series: GSE27991: Expression data of Medicago truncatula Jemalong A17 roots treated with auxin transport inhibitors GSE28171: Expression data of Medicago truncatula Jemalong A17 roots treated with S. meliloti exoA mutant or auxin transport inhibitors GSE28172: Expression data of Medicago truncatula skl1-1 roots treated with S. meliloti wild-type or auxin transport inhibitors GSE28173: Genes differentially expressed in wild-type Medicago truncatula plants during nodulation Refer to individual Series
Project description:In plants and fungi the plasma membrane proton pump generates a large proton-motive force that performs essential functions in many processes, including solute transport and the control of cell elongation. Previous studies in yeast and higher plants have indicated that phosphorylation of an auto-inhibitory domain is involved in regulating pump activity. In this report we examine the Medicago truncatula plasma membrane proton pump gene family, and in particular MtAHA5. Yeast complementation assays with phosphomimetic mutations at six candidate sites support a phosphoregulatory role for two residues, suggesting a molecular model to explain early Nod factor-induced changes in the plasma membrane proton-motive force of legume root cells.
Project description:Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.
Project description:Rhizobium and allied bacteria form symbiotic nitrogen-fixing nodules on legume roots. Plant hormones appear to play a role in nodule formation. We treated Medicago truncatula roots with auxin transport inhibitors (ATIs) N-(1-naphthyl)phthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) to induce the formation of pseudonodules. We compared the transcriptional responses of M. truncatula roots treated with ATIs to roots inoculated with Sinorhizobium meliloti. The transcriptional response of M. truncatula roots 1 and 7 days after ATI treatment were opposite to roots treated with S. meliloti.