Know more

Edouard TOURDOT

Team Flowering, Fruit Development and Environmental Constraints

Videoconference Zoom

Abstract :

Endoreduplication, during which cells increase their DNA content through successive rounds of full genome replication without cell division, is the major source of endopolyploidy in higher plants. Endoreduplication results from the capacity of cells to modify their classical cell cycle into a partial cell cycle, or endocycle, where DNA synthesis occurs independently from mitosis. In plants, endoreduplication is found in numerous organs and cell types and particularly in organs or tissues of agronomical high value, such as the fleshy fruit (pericarp) of tomato presenting high ploidy levels. At the end of tomato fruit development, the pericarp is composed of a heterogeneous population of cells in term of ploidy levels and cell sizes. In addition, at this stage, ploidy-specific gene expression profiles have been found. However, little is known about the onset and progression of endoreduplication during tomato fruit growth and its consequences on the regulation of cell size and gene expression. the aim of my PhD project was to study the heterogeneous population of cells that co-exists within the pericarp tissue and as a basis to dissect the genetic regulation of pericarp endoreduplication. Thus, I mapped the ploidy and transcriptome dynamics of the tomato fruit pericarp during early growth at three stages, 6-, 9- and 12 days post-anthesis (dpa) during fruit growth. The data showed a global shift of expression in relation to ploidy level as well as ploidy specific gene expression and that ploidy levels are already gradiently distributed in the pericarp. Using this data, a virtual map of ploidy distribution and gene expression will be done for the early development of Tomato fruit pericarp.

Jury :

M. HERNOULD, Michel - Professeur Université de Bordeaux - Examinateur
Mme BAROUX, Célia - Professeur University of Zürich -  Rapporteur
M. DE VEYLDER, Lieven - Directeur de Recherche VIB-UGent Center - Rapporteur
Mme COOKSON-WODRICH, Sarah Jane - Chargé de Recherche INRAE - Examinateur
M. ZOUINE, Mohamed - Chargé de Recherche INRAE/INP-ENSAT - Examinateur
Mme. GONZALEZ, Nathalie - Directrice de recherche INRAE - Directrice de Thèse