6533b82cfe1ef96bd128fca6

RESEARCH PRODUCT

Optimization for the determination of enzyme activities in various pea tissues

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Rapport de Stage de Master 1 EA Geapsi CT2 EA EJ1; In an environmental and political context which requests an increase of food production and a decrease in fertilizer use, pea culture seems to be one solution due on the one hand to its atmospheric nitrogen fixation and on the other hand to the important nitrogen quantity left by plants in the soil after harvest. But pea plants are very sensitive to soil water stress, that’s why scientists are searching information about enzyme activities to reveal how peas react when they are submitted to drought in the purpose of minimizing the negative impact and thus reach optimum yields. This report focuses on key enzymes involved in carbon and nitrogen metabolisms which are essentials to an optimum root and nodule growth, themselves essentials to enhance water and nitrogen nutrition of the plant is case of soil water stress. We used robotized assays to determine enzyme activities after having identified the dilutions allowing a high recovery and an optimum repeatability. Optimizations were performed on sixteen enzymes corresponding to destorage and storage enzymes, key enzymes of Krebs cycle, glycolysis and pentose phosphate pathway. The activities of these enzymes have been calculated and preferential storage and destorage pathways have been discussed. It was verified that nitrate pathway enzymes are not highly produced during atmospheric nitrogen fixation. It was observed that the carbon enzymes the most active provide carbon from sucrose, glucose and fructose and they preferentially stored it under the form of aspartate while a few was stored under the form of glutamate with glutamine as intermediary. Nodules have a more important activity of penthose phosphate pathway than root cells. This work is a first step in the characterization of root- and nodule- enzymatic activities of well watered and water stressed plants.