Agrobacterium: A genus of soil bacteria, including A. tumefaciens, A. rhizogenes, A. rubi, and A. radiobacter. A. tumefaciens is a plant pathogen that causes crown gall disease, which is characterized by tumor formation at die site of infection.
Allele: One of two or more alternative forms of a single gene.
Auxotrophic mutation: A mutation affecting an organism's ability to make a nutrient essential for its survival.
Axenic: An axenic organism is one that lives or is cultivated, usually under laboratory conditions, in the complete absence of other organisms. Axenic plants, for example, do not harbor bacterial, fungal, viral, or other living contaminants.
Bacteriophage (phage): A virus that infects bacteria.
Callus: A mass of undifferentiated plant cells cultivated on synthetic medium in the laboratory.
Catabolism: The breaking down, or degrading, of compounds by a cell or organism so that they can be further used in metabolism.
Chimeric: Composed of parts with different origins. A chimeric gene contains a promoter from one origin (e.g., plant) and a coding sequence from another (e.g., bacterial).
Chromatography: A technique used to separate compounds that bind differently to a matrix as they flow in a liquid or a gas. Single-stranded DNA can be separated from double-stranded DNA by liquid chromatography.
Cloning: The generating of many identical copies of a DNA segment by replication in a living host such as E. coli.
Codon: A set of three nucleotide bases in mRNA specifying a particular amino acid. A nonsense codon specifies a translational stop—that is, termination of protein synthesis.
Complementation: In the context here, the correction of a mutation by the addition of a wild-type, functional gene (allele).
Concatenation: Several independent DNA molecules forming a multimeric complex by covalent attachment.
Conjugation: Bacterial sex; the exchange of DNA between bacteria (see appendix 4).