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Morphogenesis of the brown alga Ectocarpus siliculosus: genetic and modeling approaches

UMR Végétaux Marins et Biomolécules, Roscoff
on 2011/04/08 at 11:00


Brown algae are photosynthetic multicellular marine organisms evolutionarily distant from both metazoans and land plants. The molecular or cellular mechanisms that govern the developmental patterning in brown algae are poorly characterized.

Here, we report the first morphogenetic mutant, étoile (etl), produced in the brown algal model Ectocarpus siliculosus. Genetic, cellular, morphometric and transcriptomic studies were performed, and showed that the single locus ETL regulates cell differentiation, cell wall thickness and Notch-domain transmembrane protein expression.

Computational modeling allowed the simulation of the étoile mutant phenotype by including a modified response to the cell neighborhood information in the transition rules used to specify WT development.

Altogether, we propose a model in which local cell-cell communication is necessary for the early establishment of the developmental pattern in this brown alga, which is later relayed (or superimposed) by the phytohormone auxin.

Related references:

A. Le Bail, B. Billoud, S. Le Panse, S. Chenivesse, B. Charrier. ETOILE regulates developmental patterning in the filamentous brown alga Ectocarpus siliculosus. The Plant Cell, in press.

JM Cock, et al. The Ectocarpus genome and the independent evolution of multicellularity in the brown algae, Nature, 465(7298):617-21,2010.

A. Le Bail, B. Billoud, N. Kowalczyk, M. Kowalczyk, M. Gicquel, S. Le Panse,S. Stewart, D. Scornet, J.M. Cock, K. Ljung and B. Charrier. Auxin metabolism and function in the multicellular brown alga Ectocarpus siliculosus. Plant Physiology, 153:128-144, 2010.

B. Billoud, A. Le Bail and B. Charrier. A stochastic 1D nearest-neighbour automaton models the early development of the brown alga Ectocarpus siliculosus. Functional Plant Biology, 35: 1014-1024, 2008.