Studies on Agrobacterium tumefaciens. IV. Nonreplication of the bacterial DNA in mung beam (Phaseolus aureus).

DNA·DNA filter hybridization and DNA solution enrichment reassociation experiments showed that no $\text{Agrobacterium tumefaciens}$ DNA was replicated in mung bean seedlings under the conditions specified in published reports for the uptake, integration, and replication of bacterial DNA in higher plants. Residual presumptive DNA hybrids that formed in a few instances were characterized by thermal chromatography on hydroxylapatite. The Tm and melting profiles of these hybrids from DNA-treated plants were the same as those from untreated control plants. The sensitivities of these procedures were sufficient to detect $\text{A. tumefaciens}$ DNA in the order of 0.005% to 0.01% of the plant genome. These results do not concur with previous reports that large pieces of DNA (at least 30%) of the plant genome of bacterial-DNA-treated-plants is made up of bacterial donor DNA.