Project description:affy_hypoctemp_medicago - The characterization of several genotypes of the model Legume Medicago truncatula showed a genetic variability for germination and hypocotyl heterotrophic growth at low temperature and optimal temperature. The most important contrast was between the accessions Jemalong A17 and F83005.5. In order to find genes differently expressed between temperatures and genotypes, the present work focuses on transcriptome profiling during hypocotyl heterotrophic growth under low (10°C) and optimal (20°C) temperature conditions for both genotypes. We used Jemalong A17 and F83005.5 seeds coming from the Medicago truncatula Biological Resource Center in Montpellier, produced in 2006. Experiments were performed in the dark to mimic pre-emergence growth. Pots (6.5 cm diameter, 10 cm high) were incubated in growth chambers either at 10°C or 20°C. They were filled with 500g sand and 100ml of a nutrient solution for young seedlings growth (Saglio and Pradet, 1980). Per pot, five scarified seeds were sown at 1.5 cm depth. Seedlings were harvested at three times: 35°Cd (degree day), 50°Cd and 100°Cd. At each timepoint, about 50 seedlings were harvested and hypocotyl lengths was measured. Hypocotyl were cut and immediately frozen in liquid nitrogen for RNA extractions.
Project description:The size and shape of plant organs are highly responsive to environmental conditions. The plant's embryonic stem, or hypocotyl, displays phenotypic plasticity, in response to light and temperature. The, hypocotyl of shade avoiding species elongate to outcompete neighbouring plants and secure access to sunlight. Similar elongation occurs in high temperature. PHYTOCHROME-INTERACTING FACTORS (PIFs) family transcription are known to be importenet players in these responses. However, it is poorly understood how environmental light and temperature interact to affect plants development. We found that low R/FR combined with warm temperature produces a synergistic hypocotyl growth response that dependent on PIF7 and the hormone auxin. We demonstrate that additional, unknown factor/s must be working downstream of the phyB-PIF-auxin module. As shade responses are known to affect yield, susceptibility to pathogens, and fruit quality in many species, our findings will improve the predictions of how plants will respond to increased ambient temperatures when grown at high density, a condition in which mutual shading occurs.
Project description:Molecular Elasticity and Adjustment of Drought Recovery Dynamics of 14N- and 15N-fertilized Legume Medicago truncatula. Climate change in conjunction with population growth necessitates a systems biology approach to characterize plant drought response and a more thorough understanding of the underlying molecular mechanisms. During drought stress and recovery, the metabolome and proteome regulate and are regulated through diverse mechanisms including synthesis and degradation. In order to study this complex regulation network, a front-end multilevel analysis is presented for the first time, investigating protein turnover, regulatory classes of proteins and metabolites as well as post translational ubiquitination of a target set of proteins during a severe stress and recovery scenario in the model legume Medicago truncatula. Evidence for enhanced translational proteome regulation was observed during drought recovery and functional clusters of differentially dynamic phases during the course of recovery were defined. The data give novel insights into molecular elasticity that enable recovery of drought stressed plants. Additionally, these results offer putative targets and metabolic pathways for future plant-bioengineering towards enhanced drought stress tolerance.
Project description:Transcriptional profiling of seeds of Medicago truncatula during maturation. To identify genes that are regulated during seed maturation in the model legume Medicago truncatula, plants at flowering stage were grown at variable light and temperature conditions under greenhouse environment (period March-June). Seeds were then collected at different stages of development. Using the Medicago NimbleGen chip, a transcriptomic analysis was performed to follow the differential expression of genes during seed maturation.
Project description:affy_hypoctemp_medicago - The characterization of several genotypes of the model Legume Medicago truncatula showed a genetic variability for germination and hypocotyl heterotrophic growth at low temperature and optimal temperature. The most important contrast was between the accessions Jemalong A17 and F83005.5. In order to find genes differently expressed between temperatures and genotypes, the present work focuses on transcriptome profiling during hypocotyl heterotrophic growth under low (10°C) and optimal (20°C) temperature conditions for both genotypes. We used Jemalong A17 and F83005.5 seeds coming from the Medicago truncatula Biological Resource Center in Montpellier, produced in 2006. Experiments were performed in the dark to mimic pre-emergence growth. Pots (6.5 cm diameter, 10 cm high) were incubated in growth chambers either at 10°C or 20°C. They were filled with 500g sand and 100ml of a nutrient solution for young seedlings growth (Saglio and Pradet, 1980). Per pot, five scarified seeds were sown at 1.5 cm depth. Seedlings were harvested at three times: 35°Cd (degree day), 50°Cd and 100°Cd. At each timepoint, about 50 seedlings were harvested and hypocotyl lengths was measured. Hypocotyl were cut and immediately frozen in liquid nitrogen for RNA extractions. Time course of 24 arrays - Medicago