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Session 5 – Plant Development, Metabolism and Physiology S5.2- The transcription factor BdDOF24 interacts with BdGAMYB and regulates the cathepsin B-like gene during Brachypodium seed germination Virginia González-de la Calle, Sara Hernando-Amado, Raquel Iglesias-Fernández, Cristina Barrero-Sicilia and Pilar Carbonero CBGP (Centro de Biotecnología y Genómica de Plantas) ETSI Agrónomos. Universidad Politécnica de Madrid. Campus de Montegancedo 28223 Pozuelo de Alarcón (Madrid) virginia.gonzalez@upm.es Abstract Transcription factors (TFs) are important regulators of gene expression. According to the specificity of the DNA-binding domain, TFs can be classified into different families. The DOF (DNA binding with One Finger) transcription factor family belongs to the class of zinc finger domains and it is characterized by a conserved region of 52 amino acid residues that is structured as a Cys2/Cys2 Zn 2+ finger that binds specifically the CREs containing the common core 5’-T/AAAAG-3’. DOF transcription factors have been associated with regulation during seed maturation and germination in cereals. We have annotated 27 putative BdDof genes of Brachypodium distachyon; their phylogenetic relationship with closely related DOF proteins from rice and barley have been established and their global expression levels in different tissues, as well as the expression pro<strong>file</strong> of the most abundant BdDof genes during seed germination have been determined. One such a gene, BdDof24 was predominantly expressed in germinating seeds. Promoters of hydrolase genes, induced upon germination, such are those encoding - amylase, EII(1-3, 1-4)- -glucanase and thiol-proteases (cathepsin B-like) contain, in addition to the 5’-T/AAAAG-3’ motif, a GA responsive element (GARE-5’-TAACAAA-3’). Two TFs binding to these two motives have been identified: BdDOF24 and BdGAMYB. We have also annotated the putative ortholog of the barley CathB-like gene (Al21): BdCathB, we established its expression pro<strong>file</strong> in different organs and throughout seed germination. The expression pattern of genes encoding BdGAMYB and BdDOF24 suggests a possible transcriptional control of the CathB gene by these TFs during seed germination. This hypothesis has been further validated by EMSA, by molecular interactions (Y2Hassays) between both TFs and by transient assays in planta. References Gubler F, Raventos D, Keys M, et al. (1999) Target genes and regulatory domains of the GAMYB transcriptional activator in cereal aleurone. Plant J 17(1): 1-9. Mena M, Cejudo FJ, Isabel-Lamoneda I, Carbonero P (2002) A role for the DOF transcription factor BPBF in the regulation of gibberellin-responsive genes in barley aleurone. Plant Physiol 130: 111-119. Moreno-Risueno MA, Martínez M, Vicente-Carbajosa J, Carbonero P (2007) The family of DOF transcription factors: from green unicellular algae to vascular plants. Mol Genet Genomics 277:379-390. Keywords Transcriptional regulation, Germination, DOF transcription factors, Hydrolases 41
Session 5 – Plant Development, Metabolism and Physiology S5.3- Rhizobacterial volatile organic compounds modulate biomass production and root architecture in Arabidopsis thaliana (L.) Heynh. and Brachypodium distachyon (L.) P. Beauv. Delaplace Pierre 1*, Varin Sébastien 1, Ormeño-Lafuente Elena 2, Spaepen Stijn 3, Saunier de Cazenave Magdalena 1, Blondiaux-Hendrick Adeline 1, Wathelet Jean-Paul 4, du Jardin Patrick 1 1 University of Liège, Gembloux Agro-Bio Tech, Plant Biology Unit, Gembloux, Belgium 2 Current address : Centre National de la Recherche Scientifique, Institut Ecologie et Environnement, Institut Méditerranéen d'Ecologie et Paléoécologie, UMR CNRS 6116, Laboratoire de Diversité Fonctionnelle des Communautés Végétales, Marseille, France 3 Centre of Microbial and Plant Genetics, K.U.Leuven, Bio-incubator, Heverlee, Belgium 4 University of Liège, Gembloux Agro-Bio Tech, General and Organic Chemistry Unit, Gembloux, Belgium * Pierre.delaplace@ulg.ac.be Abstract The ability of plants to take up water and mineral nutrients from the soil depends on their capacity to develop an extensive root system and on the interactions of roots with their soil environment, the rhizosphere. Studies of the mechanisms involved in the communication between plant growth-promoting soil micro-organisms and the root system is expected to lead to improved fertility management strategies. Up to now, the characterization of such interactions has been mainly focused on liquid diffusates but it has been recently reported that volatile organic compounds (VOC) also play a role as chemical messengers in positive interactions occurring in the rhizosphere and involving plants, bacteria, fungi and insects [1-2]. In this context, this project aims to better understand the ecophysiology of the rhizosphere of Arabidopsis thaliana and Brachypodium distachyon. For this purpose, a collection of 18 rhizobacterial strains belonging to nine genera were selected for their potential growth promotion ability. The VOC-emission capacity of each strain was measured after 24 and 48 hours of growth on agar media [3] using solid-phase microextraction followed by gas chromatography coupled to a mass spectrometer. In parallel, an in vitro screening system was set up to assess VOC-mediated plant-growth promotion ability of the selected strains. This system separates physically the plant and the bacteria while allowing interactions through VOC for 10 days within a shared atmosphere. For Arabidopsis, two inoculum sizes were considered: 2*10 5 and 2*10 6 cfu, using biological triplicates. At the end of the process, leaf and root biomasses, leaf area, primary root length, lateral root number and lateral root length were measured to assess the effects of bacterial VOC on plant growth. Experiments are in progress to characterize such parameters on Brachypodium in order to compare the response of both model species to rhizobacterial volatile perception. Acknowledgements: this work was supported by the Belgian Fonds de la Recherche Scientifique (FRFC project 2.4.591.10. and postdoctoral grant 1808458). References 1. Ryu CM, Farag MA, Hu CH, et al. (2003) Bacterial volatiles promote growth in Arabidopsis. Proc Natl Acad Sci USA 8: 4927-4932. 2. Kai M, Effmert U, Berg G, Piechulla B (2007) Volatiles of bacterial antagonists inhibit mycelial growth of the plant pathogen Rhizoctonia solani. Arch Microbiol 187: 351-360. 3. Farag MA, Ryu CM, Sumner LW, Paré PW (2006) GC–MS SPME profiling of rhizobacterial volatiles reveals prospective inducers of growth promotion and induced systemic resistance in plants. Phytochemistry 67: 2262-2268. Keywords root architecture, plant growth-promoting rhizobacteria, volatile organic compounds 42
Page 2 and 3: Acknowledgements: Institut National
Page 4 and 5: Contents Programme 4 Oral presentat
Page 6 and 7: Wednesday 19 th October, 2011 11:00
Page 8 and 9: Friday 21 st October, 2011 Biotic a
Page 10 and 11: ORAL COMMUNICATIONS 9
Page 12 and 13: Session 1 - Evolution and Natural V
Page 18 and 19: Session 2 - Cell Wall, Biomass and
Page 26 and 27: Session 3 - Tools and Bioengineerin
Page 32 and 33: Session 4 - Biotic and Abiotic Stre
Page 44 and 45: Session 5 - Plant Development, Meta
Page 74 and 75: S: Speakers’ abstracts P: Posters
Page 76 and 77: LIST OF PARTICIPANTS 75
Page 78 and 79: BOUCHABKE-COUSSA Oumaya INRA IJPB I
Page 80 and 81: GIRALDO Patricia E.T.S.I. Agronomos
Page 82 and 83: MARION-POLL Annie INRA IJPB Institu
Page 84 and 85: RENAULT Hugues CNRS - IBMP Institut
Page 86: WARD Eric Two Blades Foundation, P.

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