Legume plants are able to enter two different endosymbioses with soil prokaryotes and soil fungi, leading to nitrogen-fixing root nodules and to arbuscular mycorrhiza (AM), respectively. We applied in silico and microarray-based transcriptome profiling approaches to uncover the transcriptome of developing root nodules and AM roots of the model legume Medicago truncatula. Several hundred genes were found to be activated in different stages of either symbiosis, with almost 100 genes being co-induc ...[more]
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:To study the development of flowers and pods in Medicago truncatula, eight stages of flower and pod development (designated F1-F4 and P1-P4, respectively) were chosen for tissue harvesting. As a common reference, young but already fully developed leaves (corresponding to the third-distant node from the apices) from plants grown in the field were selected. For each stage of flower and pod development, two biological replicates were harvested, one from plants grown in the greenhouse and one from plants grown in the field.
Project description:This experiment investigates a time series of seed development in Medicago truncatula. Time points 14, 16, 20, 24, and 36 days post pollination are hybridized against a 12 days post pollination reference stage.
Project description:The transcriptome profile of arbuscular mycorrhiza established at 4 weeks post inoculation between Medicago truncatula and Glomus mosseae as well as between Medicago truncatula and Glomus intraradices is compared
Project description:ABA regulates in plants a wide range of developmental events, mediates responses to environmental stress and is necessary to proceed through seed maturation and to acquire desiccation tolerance and dormancy. Immuno-modulation is a suitable means to study ABA functions during seed maturation. Anti-ABA single chain antibody was expressed in pea seed driving LeB4-promoter (Saalbach et al., High-level expression of a single chain Fv fragment (scFv) antibody in transgenic pea seeds J. Plant Physiol. 2001 158: 529-533), which produced only a weak phenotype with slightly decreased seed weight, globulin/albumin and total nitrogen content (aABA line 16 cultivar Erbi). In another approach with a stronger, improved USP-promoter used to express the anti-ABA antibody in pea seeds a different phenotype emerged (aABA line 7, cultivar Eifel). In this line individual seed weight increased by 20 to 30% together with higher globulin and albumin content. To dissect the aABA phenotype at the molecular level, a search for genes with differential expression patterns in transgenic plant versus wild type seeds has been performed using 6k-oligo microarray analysis. cDNA probes were prepared from RNA isolated from embryo of developing seeds of wild type (12, 18, and 22 DAP) and transgenic aABA plants (12, 18, and 22 DAP), which correspond to the transition phase of seed development, and 6k-oligo microarray.
Project description:Nitrogen application to legume seeds regulates seed metabolism and composition. In order to improve nitrogen flux into the embryo, the Vicia faba amino acid permease VfAAP1 (Miranda et al. Amino acid permeases in developing seeds of Vicia faba L.: expression precedes storage protein synthesis and is regulated by amino acid supply. Plant J 2001 28: 61-72) was expressed in pea under control of the seed-specific LeB4 promotor (Bäumlein et al. Cis-analysis of a seed protein gene promoter: the conservative RY repeat CATGCATG within legumin box is essential for tissue-specific expression of a legumin gene. Plant J 1992 2: 233-239). Several transgenic lines have been generated. Mature seeds of the homozygous marker gene-free line AAP14/10 showed an increase in amino acid supply, seed nitrogen and protein content due to higher globulin fraction. The effect of VfAAP1 was tested under field conditions in two growing periods, 2005 and 2006, and the data could be confirmed. Over-expression of VfAAP1 interferes with storage protein metabolism and alters fluxes of nitrogen during seed growth. The influence of VfAAP1 on altered gene expression in developing cotyledons was analysed using a 6k-Oligo-microarray. Four developmental stages (18, 22, 26 and 30 DAP) from seeds, grown 2006, of the transgenic line AAP14/10 were hybridized against wildtype control.
Project description:During seed growth, sugar and nitrogen compounds confer regulatory control on storage activities. Thus, seed storage production could be regulated by the supply of nutrients. In order to improve nitrogen flux into the embryo, transgenic pea lines were created where ADP-glucose pyrophosphorylase (AGP) from Pisum sativum has been repressed by RNAi approach in the seeds under control of the seed-specific LeB4 promotor (Bäumlein et al. Cis-analysis of a seed protein gene promoter: the conservative RY repeat CATGCATG within legumin box is essential for tissue-specific expression of a legumin gene. Plant J 1992 2: 233-239). The plastidial enzyme AGP catalyzes the reaction of glucose-1-phosphate and ATP to pyrophosphate and ADP-glucose, which is the substrate for starch synthase. The AGP activity and transcript levels were strongly decreased in three independent transgenic lines. Repression of AGP results in a wrinkled seed phenotype obviously due to transient accumulation of free sugars during maturation. Mature seeds have reduced starch content whereas the protein concentration is higher due to increased fractions of albumins and globulins. Repression of AGP interferes with storage protein metabolism and alters fluxes of nitrogen during seed growth. The influence of decreased AGP on altered gene expression in developing cotyledons was analysed using a 6k-Oligo-microarray. Ps6kOLI1 microarray hybridization were performed using three independent biological replicates of four developmental stages (20, 25, 30 and 35 DAP) from seeds of the transgenic line iAGP-3.