title: Non-antibiotic, efficient selection for alfalfa genetic engineering.
abstract: A selectable marker gene (SMG), usually conferring resistance to an antibiotic or herbicide, is generally introduced into the plant cells with the gene(s) for the trait of interest to allow only the cells that have integrated and express the foreign sequences to regenerate into a plant. The availability of several SMGs for each plant species is useful for both basic and applied research to combine several genes of interest in the same plant. A selection system based on gabaculine (3-amino-2,3-dihydrobenzoic acid) as the selective substance and the bacterial hemL gene [encoding a mutant for of the enzyme glutamate 1-semialdehyde aminotransferase (GSA-AT)] as the SMG was previously used for genetic transformation of tobacco. The hemL gene is a good candidate for a safe SMG, because GSA-AT is present in all plants and is likely involved in one metabolic step only, so that unintended effects of its overexpression in plants are not probable. In this work, we have compared this new selection system with the conventional, kanamycin-based system for alfalfa Agrobacterium-mediated transformation. The hemL and NptII genes were placed together into a T-DNA under the control of identical promoters and terminators. We show that the gabaculine-based system is more efficient than the conventional, kanamycin-based system. The inheritance of hemL was Mendelian, and no obvious phenotypic effect of its expression was observed.
authors.affiliation: Dipartimento di Biologia Vegetale Biotecnologie Agroambientali e Zootecniche, Università degli Studi di Perugia, Borgo XX giugno 74, 06121 Perugia, Italy. roselli@unipg.it
authors.forename: Daniele
authors.initials: D
authors.lastname: Rosellini
authors.forename: Stefano
authors.initials: S
authors.lastname: Capomaccio
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Ferradini
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Savo Sardaro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Nicolia
authors.forename: Fabio
authors.initials: F
authors.lastname: Veronesi
mesh_terms: D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering / Q000379:methods*; D005819:Genetic Markers / Q000235:genetics; D000455:Medicago sativa / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012641:Selection, Genetic; D050610:Sodium-Phosphate Cotransporter Proteins, Type II / Q000235:genetics / Q000378:metabolism; D046509:Tissue Culture Techniques
chemical_list: D003509:Cyclohexanecarboxylic Acids; D005819:Genetic Markers; D010940:Plant Proteins; D050610:Sodium-Phosphate Cotransporter Proteins, Type II; C012987:gabaculine