Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)
Jeudi 29 septembre 2011
Salle 104 (Château) à 14h
Molecular networks regulating leaf growth
Plant System Biology – VIB, Ghent University, Belgium
Final leaf size is tightly controlled by genes that spatially and temporally coordinate cell proliferation and cell expansion. By combining genetic and molecular approaches, we aim at understanding the regulatory network controlling leaf size in Arabidopsis. We first performed a comparative analysis of five transgenic lines that produce enlarged leaves under standardized environmental conditions. We showed that the increase in leaf area in these plants depends on leaf position and growth conditions, and that all five lines affect leaf size differently. However, in all cases, an increase in cell number is responsible for the size enlargement. By analyzing hormone levels, transcriptome and metabolome, we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between these datasets indicates that enhanced organ growth is governed by different, seemingly independent pathways, however possibly interconnected. In order to build a more complete growth regulatory network, we aim at identifying new regulators of leaf development by applying different approaches. For example, as cell cycle has been shown to have an important role in the determination of final leaf size, we are analysing the effect on leaf growth of the mis-expression of genes encoding cell cycle interactors. Many more genes have been identified that enhance leaf size when over-expressed or down-regulated. By analysing transgenic lines simultaneously overexpressing two growth-enhancing genes, we aim at determining the interactions between the multiple pathways converging on organ size control in Arabidopsis.
Contact : Christine Granier