Plant Science 161 (2001) 559–567 Somatic embryo formation in Arabidopsis and eggplant is associated with expression of a glycine-rich protein gene (Atgrp -5 ) Cla ´udia Magioli a , Rosa Maria Barro ˆco b , Carla Andrea Benı ´cio Rocha a , Lygia Dolores de Santiago-Fernandes c , Elisabeth Mansur d , Gilbert Engler e , Marcia Margis-Pinheiro a , Gilberto Sachetto-Martins a, * a Laborato ´rio de Gene ´tica Molecular Vegetal, Departamento de Gene ´tica, Uniersidade, Federal do Rio de Janeiro, C.P. 68011, Brazil b Department of Molecular and Plant Genetics, Flanders Interuniersity Institute for Biotechnology, Uniersiteit Gent, B-9000 Gent, Belgium c Laborato ´rio de Anatomia Vegetal, Departamento de Bota ˆnica, Museu Nacional, Uniersidade Federal do Rio de Janeiro C.P. 22940 -040, Brazil d Laborato ´rio de Micropropagac ¸a ˜o e Transformac ¸a ˜o de Plantas, Departamento de Biologia Celular e Gene ´tica /CEPUERJ, Uniersidade do Estado do Rio de Janeiro, Brazil e Laboratoire Associe ´ de l’Institut National de la Recherche Agronomique (France), Uniersiteit Gent, B-9000 Gent, Belgium Received 28 February 2001; received in revised form 2 May 2001; accepted 3 May 2001 Abstract The isolation of embryogenesis-associated genes and the characterization of their roles during embryo development are important steps towards the elucidation of the molecular mechanisms controlling embryo morphogenesis. Somatic embryogenesis continues to be an effective model for studying gene expression in embryo development. We report the analysis of the transcriptional expression of a glycine-rich gene (Atgrp -5 ) during somatic embryo morphogenesis. Arabidopsis thaliana transgenic lines carrying chimeric constructs containing the -glucuronidase (GUS) reporter gene under the control of the Atgrp -5 promoter were used to analyze its expression pattern during somatic embryogenesis. To evaluate whether Atgrp -5 expression observed in Arabidopsis reflects a general pattern during somatic embryogenesis, transgenic eggplant (Solanum melongena L.) was used as non-homologous embryogenic system. High promoter activity was detected in all cells of pro-embryogenic cell clusters and somatic embryos from globular to torpedo stages. During the transition from torpedo to cotyledonar stage the Atgrp -5 gene was gradually turned off and, in mature embryos, its promoter activity was restricted to the protoderm. mRNA in situ hybridization on Arabidopsis somatic embryo cultures have confirmed the expression pattern observed by GUS histochemical assays. These results indicate that Atgrp -5 is expressed in cells that undergo the first anatomical modifications leading to somatic embryo development. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Arabidopsis thaliana; Developmental gene expression; Eggplant; Glycine-rich protein (GRP); Pro-embryogenic masses; Somatic embryogenesis www.elsevier.com/locate/plantsci 1. Introduction During embryogenesis the basic body plan of the mature plant is generated. This involves the production of shoot and root meristems, cotyledons, radicle, and hypocotyl, resulting in the establishment of the apical- basal axis of the plant and the formation of radial pattern elements, epidermis, ground tissue, and vascula- ture. These pattern elements are established early in embryogenesis and are stably maintained throughout the plant’s lifetime [1 – 4]. In order to better understand embryo morphogenesis and development, several exper- imental approaches have been applied, such as micro- surgical manipulations involving the ablation of specific cellular groups and characterization of embryo mutants deficient at specific stages of morphogenesis [5 – 7]. Despite the number of studies that focus on the embryogenic program, the molecular basis for this cru- cial stage of plant development is still unclear. The gene expression pattern and its regulation during early events leading to embryogenesis and consequently plant * Corresponding author. Tel/fax: +55-21-590-0111. E-mail address: sachetto@biologia.ufrj.br (G. Sachetto-Martins). 0168-9452/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII:S0168-9452(01)00443-5