TABLE 3.
Entry exclusion of octopine-type and nopaline-type Ti plasmids by homologous and heterologous recipients
| Recipient | Donor | Relevant protein(s) expressed in recipient | No. of transconjugantsa per donor (SD) | Exclusion coefficientb |
|---|---|---|---|---|
| Homologous recipients | ||||
| R10(pPZP201) | WCF5(pJZ381)c | None | 0.94 (0.2) | 1 |
| R10(pHC335) | WCF5(pJZ381) | TraR, TraI, TraA to TraH, TrbB to TrbL | 0.003 (0.001) | 313 |
| C58(pPZP201) | HC158(pJZ381)d | None | 0.22 (0.03) | 1 |
| C58(pHC335) | HC158(pJZ381) | TraR, TraI, TraA to TraH, TrbB to TrbL | 0.0008 (0.0004) | 275 |
| Heterologous recipients | ||||
| C58(pPZP201) | WCF5(pJZ381) | None | 0.032 (0.01) | 1 |
| C58(pHC335) | WCF5(pJZ381) | TraR, TraI, TraA to TraH, TrbB to TrbL | 0.005 (0.002) | 64 |
| R10(pPZP201) | HC158(pJZ381) | None | 0.001 (0.001) | 1 |
| R10(pHC335) | HC158(pJZ381) | TraR, TraI, TraA to TraH, TrbB to TrbL | <0.00001e | >100 |
| Recipients lacking a Ti plasmid | ||||
| C58C1RS(pPZP201) | WCF5(pJZ381) | None | 0.47 (0.22) | 1 |
| C58C1RS(pHC335) | WCF5(pJZ381) | TraR | 0.55 (0.08) | 0.85 |
| C58C1RS(pPZP201) | HC158(pJZ381) | None | 0.35 (0.035) | 1 |
| C58C1RS(pHC335) | HC158(pJZ381) | TraR | 0.42 (0.13) | 0.8 |
Transconjugants were selected using the Kmr gene of the Ti plasmid and the Spr gene of pPZP201 or pHC335. In mock conjugations, we did not detect spontaneous resistance to either kanamycin or spectinomycin. The data are the averages of results from three independent experiments, with the standard deviations shown in parentheses.
The exclusion coefficient is the number of transconjugants per donor for the no-exclusion control (lines with exclusion coefficients of 1) divided by the number of transconjugants of the tested recipient strain per donor.
R10-derived strain containing a Kmr gene on the octopine-type Ti plasmid.
C58-derived strain containing a Kmr gene on the nopaline-type Ti plasmid.
No transconjugants were detected in an assay mixture containing 100,000 donor bacteria.