Agrobacterium transformation of Arabidopsis thaliana roots: a quantitative assay.

Arabidopsis thaliana has become a major model system for investigating plant molecular, genetic, and biochemical processes. Arabidopsis is highly susceptible to Agrobacterium-mediated transformation using "flower dip" and "vacuum infiltration" protocols. However, Arabidopsis has also become a major system to investigate the mechanism of Agrobacterium-mediated transformation of somatic tissue. Such investigations require a reproducible, quantitative assay system to determine transformation frequency. We describe here an Arabidopsis root transformation protocol that can be used to determine transformation frequencies for wild-type and mutant Agrobacterium strains and for various Arabidopsis wild-type and mutant lines.