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Published on: January 10, 2019
Compatibility of pTM89, a new F-like R factor, and of derivative plasmids
Abstract:
pTM89, an fi+ R factor that controls the production of repressed F-type pili, is incompatible with plasmids belonging to the FII and P groups. The results of P1 transduction show that all of the resistance markers of pTM89 are part of a single replicon, which also includes RTF. When the compatibility of different derivative plasmids was investigated, it was found that they fall into two classes. Those of the first class have lost the compatibility of pTM89 for the P group but are still incompatible with FII group, whereas those of the second class are compatible with plasmids of both groups. Plasmids of the latter class that are also compatible with each other and, therefore, apparently lack any determinant for compatibility are genetically stable and self-transmissible. It appears, therefore, that compatibility between plasmids cannot be explained by the hypothesis of competition for a maintenance site.
Insights
This study investigates plasmid pTM89 compatibility. Results show derivative plasmids exhibit varying compatibility, suggesting plasmid maintenance sites may not solely determine compatibility.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Plasmid pTM89, an fi+ R factor, regulates F-type pilus production.
- pTM89 demonstrates incompatibility with FII and P group plasmids.
- Resistance markers on pTM89 are linked to a single replicon, including RTF.
Purpose of the Study:
- To investigate the compatibility of pTM89 and its derivatives with other plasmid groups.
- To understand the genetic basis of plasmid compatibility.
Main Methods:
- P1 transduction was used to analyze resistance markers.
- Compatibility of derivative plasmids with FII and P groups was assessed.
Main Results:
- Derivative plasmids were classified into two groups based on compatibility.
- One class lost P group compatibility but retained FII incompatibility.
- The second class was compatible with both FII and P groups, and with each other.
- These compatible derivatives were genetically stable and self-transmissible.
Conclusions:
- Plasmid compatibility is not solely explained by competition for a maintenance site.
- The findings challenge existing hypotheses on plasmid coexistence mechanisms.
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