Octopine and nopaline metabolism in Agrobacterium tumefaciens and crown gall tumor cells: role of plasmid genes

Abstract

Crown gall tumors produced octopine or nopaline or neither compound, depending on the bacterial strain that incited the tumor. The genes specifying production of octopine or nopaline by the tumor were transferred to recipient bacterial strains when the large plasmid associated with virulence was transferred by either conjugation or deoxyribonucleic acid-mediated transformation. Our results, which confirm the work of others (Bomhoff et al., 1976; Goldman et al., 1968; Petit et al., 1970), indicate that, in general, the strains that utilize octopine induce tumors that synthesize octopine, and those that utilize nopaline induce tumors that synthesize nopaline. However, there were several notable exceptions. One class utilized both octopine and nopaline, but the tumors induced by these strains produced only nopaline. Another class utilized nopaline, but their tumors synthesized neither nopaline nor octopine. Mutants were isolated from a number of either octopine-or nopaline-utilizing strains that no longer could utilize the relevant guanido amino acid. These strains, which were mutant in the gene specifying octopine or nopaline oxidase, still retained the permease for these amino acids as well as virulence. Tumors induced by these mutants still synthesized approximately the same levels of octopine and nopaline as tumors induced by their parents. These results suggest that the plasmid gene that determines production of octopine or nopaline by the tumor is distinct from the plasmid gene that determines their catabolism by the bacteria.

Agrobacterium tumefaciens can obtain sulphur from an opine that is synthesized by octopine synthase using S‐methylmethionine as a substrate

“…Opines have long been known to induce genes required for their uptake and catabolism (Montoya et al, 1977;Klapwijk et al, 1978;von Lintig et al, 1991). Octopine has been reported to activate the transcription of the occ operon by binding to OccR (Habeeb et al, 1991).…”

Opine utilization by Spanish isolates of Agrobacterium tumefaciens

“…Strains from grapevine utilizing both octopine and nopaline were also found; Montoya et al (1977) have reported that in wild-type strains taking up both octopine and nopaline, only nopaline uptake is plasmid encoded. Spanish isolates might be of this type or else they might be transconjugants that harbour a plasmid cointegrate of the octopine and nopaline plasmids (Hooykaas et ai, 1979).…”

Simple rules govern the diversity of bacterial nicotianamine-like metallophores

“…In plants, diverse opines are found inside crown gall tumors (for example nopaline, agropine, octopine, mannopine or D-L and L-L-succinamopine) that are induced by plant pathogenic bacteria as Agrobacterium tumifaciens [18]. In this case, the opines serve as nutrients conferring selective growth advantages to the opine-producing and opine-utilizing microorganisms [19,20].…”