Pierre Chambrier | École Normale Supérieure de Lyon (original) (raw)

Uploads

Papers by Pierre Chambrier

HAL (Le Centre pour la Communication Scientifique Directe), Mar 10, 1997

The Plant Cell, Oct 7, 2019

Parasitology Research, 1999

Journal of Experimental Botany, Sep 5, 2010

Frontiers in Plant Science, Feb 2, 2016

Plant Physiology, Dec 16, 2005

Current Biology, Apr 1, 2008

Floral homeotic MADS-box transcription factors ensure the correct morphogenesis of floral organs,... more Floral homeotic MADS-box transcription factors ensure the correct morphogenesis of floral organs, which are organized in different cell layers deriving from the meristematic L1, L2 and L3 layers. How cells from these distinct layers acquire their respective identity and coordinate their growth to ensure normal floral organ morphogenesis is unresolved. Here, we study petunia petals that form a limb and tube through congenital fusion, a complex morphology that coevolved with pollinators. We have identified petunia mutants expressing the B-class MADS-box gene PhDEF in the epidermis or in the mesophyll of the petal only, called wico and star respectively. Strikingly, wico flowers form a strongly reduced tube while their limbs are almost normal, while star flowers form a normal tube but very reduced and unpigmented limbs, showing that petunia petal morphogenesis is highly modular. Comparative transcriptome analysis of star, wico and wild-type petals revealed a strong down-regulation of t...

Petunia hybrida (or garden petunia) is worldwide one of the most popular bedding plants. At the s... more Petunia hybrida (or garden petunia) is worldwide one of the most popular bedding plants. At the same time, petunia has a decades-long history as a model species for scientific research to study a variety of processes, including floral organ development. Here we explain the genetic basis of floral organ identity in a comprehensible manner and illustrate the potential of floral organ identity mutants for ornamental plant breeding, using petunia as an example. Although the B- and C-floral organ identity functions are well conserved at the molecular level, indicating broad applicability, different species may exhibit significant differences in the degree of redundancy versus subfunctionalization/specialization among duplicated pairs of the homeotic genes. This is a direct consequence of the complex origin of different plant genomes, which were shaped by whole-genome, large and small-scale duplication events, often leading to (partial) genetic redundancy. Since classical genetic screens ...

Communications Biology, 2020

In cucurbits, CmWIP1 is a master gene controlling sex determination. To bring new insight in the ... more In cucurbits, CmWIP1 is a master gene controlling sex determination. To bring new insight in the function of CmWIP1, we investigated two Arabidopsis WIP transcription factors, AtWIP1/TT1 and AtWIP2/NTT. Using an inducible system we showed that WIPs are powerful inhibitor of growth and inducer of cell death. Using ChIP-seq and RNA-seq we revealed that most of the up-regulated genes bound by WIPs display a W-box motif, associated with stress signaling. In contrast, the down-regulated genes contain a GAGA motif, a known target of polycomb repressive complex. To validate the role of WIP proteins in inhibition of growth, we expressed AtWIP1/TT1 in carpel primordia and obtained male flowers, mimicking CmWIP1 function in melon. Using other promoters, we further demonstrated that WIPs can trigger growth arrest of both vegetative and reproductive organs. Our data supports an evolutionary conserved role of WIPs in recruiting gene networks controlling growth and adaptation to stress.

Journal of experimental botany, Jan 22, 2016

We provide an overview of methods and workflows that can be used to investigate the topologies of... more We provide an overview of methods and workflows that can be used to investigate the topologies of Gene Regulatory Networks (GRNs) in the context of plant evolutionary-developmental (evo-devo) biology. Many of the species that occupy key positions in plant phylogeny are poorly adapted as laboratory models and so we focus here on techniques that can be efficiently applied to both model and non-model species of interest to plant evo-devo. We outline methods that can be used to describe gene expression patterns and also to elucidate the transcriptional, post-transcriptional, and epigenetic regulatory mechanisms underlying these patterns, in any plant species with a sequenced genome. We furthermore describe how the technique of Protein Resurrection can be used to confirm inferences on ancestral GRNs and also to provide otherwise-inaccessible points of reference in evolutionary histories by exploiting paralogues generated in gene and whole genome duplication events. Finally, we argue for ...

Frontiers in plant science, 2016

Plant biology in general, and plant evo-devo in particular would strongly benefit from a broader ... more Plant biology in general, and plant evo-devo in particular would strongly benefit from a broader range of available model systems. In recent years, technological advances have facilitated the analysis and comparison of individual gene functions in multiple species, representing now a fairly wide taxonomic range of the plant kingdom. Because genes are embedded in gene networks, studying evolution of gene function ultimately should be put in the context of studying the evolution of entire gene networks, since changes in the function of a single gene will normally go together with further changes in its network environment. For this reason, plant comparative biology/evo-devo will require the availability of a defined set of 'super' models occupying key taxonomic positions, in which performing gene functional analysis and testing genetic interactions ideally is as straightforward as, e.g., in Arabidopsis. Here we review why petunia has the potential to become one of these future...

Annals of botany, 2007

CRABS CLAW (CRC) encodes a transcription factor of the YABBY family that plays important roles in... more CRABS CLAW (CRC) encodes a transcription factor of the YABBY family that plays important roles in carpel and nectary development in Arabidopsis thaliana. Combined evolutionary and developmental studies suggest an ancestor of the CRC gene to have controlled carpel development in the last common ancestor of the angiosperms. Roles for CRC orthologues in leaf development and carpel specification in rice, and in nectary development in core eudicots, have accordingly been interpreted as derived. The aim of this study was to assess the capacity of CRC orthologues from a basal angiosperm and from rice to complement CRC mutants of arabidopsis. These experiments were designed to test the hypothesized ancestral role of CRC in the angiosperms, and to indicate whether putatively novel roles of various CRC orthologues resulted from changes to their encoded proteins, or from other molecular evolutionary events. The crc-1 mutant of arabidopsis was genetically transformed with the coding sequences o...

The Plant Journal, 2015

SummarySmall non‐coding RNAs are versatile riboregulators that control gene expression at the tra... more SummarySmall non‐coding RNAs are versatile riboregulators that control gene expression at the transcriptional or post‐transcriptional level, governing many facets of plant development. Here we present evidence for the existence of a 24 nt small RNA (named small1) that is complementary to the 3′ UTR of OCL1 (Outer Cell Layer1), the founding member of the maize HD–ZIP IV gene family encoding plant‐specific transcription factors that are mainly involved in epidermis differentiation and specialization. The biogenesis of small1 depends on DICER‐like 3 (DCL3), RNA‐dependent RNA polymerase 2 (RDR2) and RNA polymerase IV, components that are usually required for RNA‐dependent DNA‐methylation. Unexpectedly, GFP sensor experiments in transient and stable transformation systems revealed that small1 may regulate its target at the post‐transcriptional level, mainly through translational repression. This translational repression is attenuated in an rdr2 mutant background in which small1 does not ...