title: Comparison of four constitutive promoters for the expression of transgenes in the tropical nitrogen-fixing tree Allocasuarina verticillata.
abstract: Allocasuarina verticillata is an actinorhizal tree that lives in symbiotic association with a nitrogen fixing actinomycete called Frankia. In the search for promoters that drive strong constitutive expression in this tropical tree, we studied the organ specificity of four different constitutive promoters (CaMV 35S, e35S, e35S-4ocs and UBQ1 from Arabidopsis thaliana) in stably transformed A. verticillata plants. The ss-glucuronidase (gus) gene was used as a reporter and expression studies were carried out by histochemical analyses on shoots, roots and actinorhizal nodules. While the 35S promoter was poorly expressed in the shoot apex and lateral roots, both the e35S and e35S-4ocs were found to drive high constitutive expression in the transgenic non-nodulated plants. In contrast, the UBQ1 promoter was very poorly expressed and appeared unsuitable for A. verticillata. We also showed that none of the promoters studied were active in the nodule infected cells, whatever the developmental stage studied.
authors.affiliation: Groupe Rhizogénèse Symbiotique, UMR 1098, IRD (Institut de Recherche pour le Développement), 911 avenue Agropolis, BP 5045, 34394 Montpellier Cedex 5, France.
authors.forename: Mariana
authors.initials: M
authors.lastname: Obertello
authors.forename: Carole
authors.initials: C
authors.lastname: Santi
authors.forename: Mame-Oureye
authors.initials: MO
authors.lastname: Sy
authors.forename: Laurent
authors.initials: L
authors.lastname: Laplaze
authors.forename: Florence
authors.initials: F
authors.lastname: Auguy
authors.forename: Didier
authors.initials: D
authors.lastname: Bogusz
authors.forename: Claudine
authors.initials: C
authors.lastname: Franche
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D015870:Gene Expression / Q000502:physiology*; D005966:Glucuronidase / Q000235:genetics; D009586:Nitrogen Fixation; D018517:Plant Roots / Q000201:enzymology; D018520:Plant Shoots / Q000201:enzymology; D030821:Plants, Genetically Modified; D010957:Plasmids; D011401:Promoter Regions, Genetic; D019076:Transgenes; D014197:Trees / Q000235:genetics* / Q000502:physiology
chemical_list: D005966:Glucuronidase