Indoleacetic acid production: a plasmid function of Agrobacterium tumefaciens C58.

Indoleacetic acid (IAA) production is regulated by the 117 Mdalton pTi plasmid that is harbored by the crown gall bacterium $\text{Agrobacterium tumefaciens}$ strain C-58. In the presence of tyrosine, about 5- to 10-fold higher IAA production (0.8–0.9 μg/ml) occurs in strain C-58 than in the plasmidless avirulent derivative strain NT1. The high level of IAA production is restored when the plasmid is reintroduced into strain NT1.