plasmid carriage

Deep research

Generated by just research-trait; source: research/traits/genomics/plasmid_carriage-deep-research-falcon.md

# TraitMech curation report: plasmid carriage

**Trait:** `traitmech:000090`  
**Label:** plasmid carriage  
**Category:** GENOMICS | **Kind:** CLASS | **Status:** REVIEWED  
**Parent:** `traitmech:000089`

## 1. Scope summary

Plasmid carriage is the state in which a microbial cell possesses at least one **autonomously replicating, extrachromosomal DNA replicon**. Most plasmids are circular, but circularity should not be required because linear plasmids occur. Likewise, conjugative mobility, antimicrobial-resistance genes, virulence genes, and high copy number are optional properties rather than defining criteria. A 2023 survey describes plasmids as autonomously replicating mobile genetic elements and explicitly notes both circular and linear forms; only 22% of its identified *Salmonella* MOB-clusters were associated with a known resistance gene. Thus, “plasmid carriage” must not be made synonymous with AMR carriage (robertson2023aglobalsurvey pages 1-2).

The graph should represent two routes into and maintenance of the state:

1. **Acquisition/establishment:** conjugation or another DNA-transfer route → evasion of recipient defense → autonomous replication → plasmid carriage.
2. **Vertical maintenance:** replication/copy-number control + segregation/partition + multimer resolution and, in some plasmids, toxin–antitoxin systems → reduced plasmid loss → persistent carriage.

Host fitness, positive selection, compensatory evolution, cell-envelope properties, co-resident plasmids, and ecological context modify these routes. Contemporary plasmid ecology treats host fitness effects and horizontal transmission rate as the principal population-level controls; conjugation affects both initial acquisition and persistence by replenishing plasmid-bearing cells (dimitriu2024variousplasmidstrategies pages 1-2).

### Boundary cases

- **Include:** cells carrying one or more autonomous plasmids; low- or high-copy plasmids; circular or linear plasmids; conjugative, mobilizable, or non-mobilizable plasmids.
- **Exclude:** an integrative conjugative element residing only in the chromosome; a resistance gene integrated into the chromosome after leaving a plasmid; transient transferred DNA that never establishes autonomous replication; and naked plasmid DNA outside a cell.
- **Do not equate with:** plasmid persistence, conjugation, plasmid copy number, plasmid-borne AMR, virulence, or metabolic phenotypes. These are causes, modifiers, measurements, or consequences of carriage.
- **Assay caution:** short-read replicon calls and MOB-suite reconstructions are evidence for predicted carriage, not necessarily direct observation of an intact autonomous molecule. Long-read closure, plasmid extraction, copy-number measurements, or demonstrated transfer/stability provide stronger evidence.

## 2. Candidate nodes and ontology grounding

Identifiers below are restricted to high-confidence established terms. Family- or plasmid-specific entities are deliberately left label-only where a stable cross-database identifier was not verified.

### A. Trait and physical entities

- **plasmid carriage:** `traitmech:000090`
- **plasmid:** GO:0005727
- **plasmid DNA / extrachromosomal replicon:** label-only candidate if the data model distinguishes molecule from localization
- **plasmid replication origin (oriV):** label-only
- **plasmid multimer:** label-only
- **donor cell, recipient cell, transconjugant:** label-only role nodes
- **cytoplasm:** GO:0005737

### B. Processes and molecular functions

- **DNA replication:** GO:0006260
- **DNA-templated transcription:** GO:0006351
- **DNA recombination:** GO:0006310
- **conjugation:** GO:0000746
- **DNA-mediated transformation:** GO:0009294
- **DNA methylation:** GO:0006306
- **DNA binding:** GO:0003677
- **DNA-binding transcription-factor activity:** GO:0003700
- **endonuclease activity:** GO:0004519
- **transposase activity:** GO:0004803
- **biofilm formation:** GO:0042710
- **cell death:** GO:0008219
- **plasmid replication, plasmid partition, multimer resolution, post-segregational killing, plasmid loss, compensatory evolution, plasmid establishment, and plasmid incompatibility:** retain as label-only candidates unless the curation environment supplies verified ontology terms.

### C. Genes, proteins, RNAs, and complexes

**Core inheritance modules**

- Rep replication initiator and oriV

Showing the first 60 of 276 lines of findings; the linked file also carries the run's front matter and the prompt it was given — read the full report.