Organ Size Regulation

organMolecular systems governing leaf growth: from genes to networks
Size control of multicellular organisms poses a longstanding biological question that has always fascinated scientists. Currently the question is far from being resolved because of the complexity of and interconnection between cell division and cell expansion, two different events necessary to form a mature organ.

Because of the importance of plants for food and renewable energy sources, dissecting the genetic networks underlying plant growth and organ size is becoming a high priority in plant science worldwide. Our long term goal is therefore to unravel the molecular pathways that govern leaf size by using Arabidopsis as a model plant..

To extend our knowledge of the genetic networks controlling leaf size, we aim at answering the following questions: What changes in growth phenotype can we observed? Where/in which leaves is the phenotype observed? When during development are the changes occurring and which are the cellular processes that are affected? Why do changes in molecular mechanisms drive these phenotypic changes?

 

We therefore combine physiological (growth analysis on mutants or natural variants) and molecular (e.g. transcript and metabolite profiling, protein-protein interactions) analyses to study the mode of action of growth promoting genes and identify new potential growth regulators. We have, in the past, identified and studied several growth promoting genes and we are now further investigating their function as well as their targets and/or interacting proteins to expand the growth regulatory network. To discover new growth regulators and growth regulatory pathways in a non-a-priori manner, we also make use of a chemical genomics approach. We will use our expertise in imaging to screen chemical libraries of small molecules to find compounds positively influencing leaf growth. Whereas much research is done on single genes affecting leaf size, the interactions between these growth regulators remain unexplored. Therefore, to build a more integrated growth regulatory network, we study the connections existing between the different molecular players of the various processes driving leaf growth. Our final aim is to be able model regulatory networks to understand leaf growth.

People involved: Nathalie Gonzalez (Project leader), Stijn Dhondt, Hannes Vanhaeren, Jonas Blomme, Youn-Joeng Nam, Judith Van Dingenen, Jasmien Vercruysse, Liesbeth De Milde, Twiggy Van Daele, Mattias Vermeersch

Selected publications:

Gonzalez N, Pauwels L, Baekelandt A, De Milde L, Van Leene J, Besbrugge N, Heyndrickx KS, Pérez AC, Durand AN, De Clercq R, Van De Slijke E, Vanden Bossche R, Eeckhout D, Gevaert K, Vandepoele K, De Jaeger G, Goossens A, Inzé D. (2015) A Repressor Protein Complex Regulates Leaf Growth in Arabidopsis. Plant Cell. PMID:26232487

Vanhaeren H, Gonzalez N, Inzé D. (2015) A Journey Through a Leaf: Phenomics Analysis of Leaf Growth in Arabidopsis thaliana. Arabidopsis Book. PMID: 26217168

Vercruyssen L, Tognetti VB, Gonzalez N, Van Dingenen J, De Milde L, Bielach A, De Rycke R, Van Breusegem F, Inzé D. (2015) GROWTH REGULATING FACTOR5 stimulates Arabidopsis chloroplast division, photosynthesis, and leaf longevity. Plant Physiol. Mar;167(3):817-32 PMID: 25604530

Vanhaeren H, Gonzalez N, Coppens F, De Milde L, Van Daele T, Vermeersch M, Eloy NB, Storme V, Inzé D. (2014) Combining growth-promoting genes leads to positive epistasis in Arabidopsis thaliana. Elife. PMID: 24843021

Vercruyssen L, Verkest A, Gonzalez N, Heyndrickx KS, Eeckhout D, Han SK, Jégu T, Archacki R, Van Leene J, Andriankaja M, De Bodt S, Abeel T, Coppens F, Dhondt S, De Milde L, Vermeersch M, Maleux K, Gevaert K, Jerzmanowski A, Benhamed M, Wagner D, Vandepoele K, De Jaeger G, Inzé D. (2014) ANGUSTIFOLIA3 binds to SWI/SNF chromatin remodeling complexes to regulate transcription during Arabidopsis leaf development. Plant Cell. PMID: 24443518

Gonzalez N., Vanhaeren H., Inzé D. (2012) Leaf size control: complex coordination of cell division and expansion. Trends Plant Sci. 17(6):332-40.

Eloy NB., Gonzalez N., Van Leene J., Maleux K., Vanhaeren H., De Milde L., Dhondt S., Vercruysse L., Witters E., Mercier R., Cromer L., Beemster GT., Remaut H., Van Montagu MC., De Jaeger G., Ferreira PC., Inzé D. (2012) SAMBA, a plant-specific anaphase-promoting complex/cyclosome regulator is involved in early development and A-type cyclin stabilization. Proc Natl Acad Sci U S A. 109(34):13853-8.

Andriankaja M., Dhondt S., De Bodt S., Vanhaeren H., Coppens F., De Milde L., Mühlenbock P., Skirycz A., Gonzalez N., Beemster G.T., Inzé D. (2012) Exit from proliferation during leaf development in Arabidopsis thaliana: a not-so-gradual process. Dev Cell. 22(1):64-78.

Vercruyssen L., Gonzalez N., Werner T., Schmülling T. and Inzé D. (2011) Combining enhanced root and shoot growth reveals crosstalk between pathways that control plant organ size in Arabidopsis. Plant Physiol. 155(3):1339-52.