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Caractérisation physiologique, génétique et moléculaire de la mise en réserve de l’azote (VSP) chez Cichorium intybus (endive). Conséquences sur la qualité morphologique et sanitaire du chicon

Abstract : An approach combining plant physiology, genetics and molecular biology allowed us to characterize the protein reserves of witloof chicory (Cichorium intybus l. ) and to study the effect of nitrogen supply during the vegetative growth on nitrogen storage in the tuberized root and on Belgium endive (chicon) quality. The first part of the work consisted in identifying a 17 kDa vegetative storage protein (VSP) in the tuberized root and characterizing it at the biochemical and molecular levels. The study of the regulation of VSP expression by nitrate indicates that nitrogen limitation during the vegetative phase delays the accumulation of the storage protein and alters its remobilization during forcing. Furthermore, the VSP protein and/or its messenger are present in rootlets, veins and leaf blades. In addition, the protein shows high homology with several allergens and PR proteins. These results suggest that the VSP protein is a temporary and long-term nitrogen reserve and may have a role in plant defense responses. In a second step, we showed that nitrogen fertilization during the vegetative phase strongly influences the morphological and sanitary quality of chicon. Our results indicate that this effect is genotype dependent, the four lines studied being divided into two groups according to their sensitivity to nitrate. These two groups were confirmed by genetic and physiological characterization of the lines. The root molecules responsible for the effect of nitrogen on endive quality were investigated. Carbon metabolism is not involved in the nitrate signal transduction pathway. Nitrogen metabolism differed strongly between lines. However, no strict correlation between root nitrogen compounds and the quality level obtained could be established. The role of nitrogen compounds as developmental regulatory signals thus seems to be questioned.
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https://hal.inrae.fr/tel-03322773
Contributor : Céline Richard-Molard <>
Submitted on : Thursday, August 19, 2021 - 5:16:59 PM
Last modification on : Thursday, August 26, 2021 - 3:23:52 AM

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  • HAL Id : tel-03322773, version 1

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Céline Richard-Molard. Caractérisation physiologique, génétique et moléculaire de la mise en réserve de l’azote (VSP) chez Cichorium intybus (endive). Conséquences sur la qualité morphologique et sanitaire du chicon. Sciences du Vivant [q-bio]. Ecole Nationale Agronomique de Rennes, 1999. Français. ⟨tel-03322773⟩

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