Table 3 Genetic mobility via different mechanisms in Salmonella spp.

From: Bacterial chromosomal mobility via lateral transduction exceeds that of classical mobile genetic elements

 

Accession

DNA transferred

HGT mechanism

Transfer frequency (TE/donor CFU)a

Source for transfer frequency data

Cargo capacity rateb

Relative frequency of genetic mobilityc

Mobilome component

Plasmids

 pSLT

CP001362

Plasmid

Conjugation

4.20 × 10−6 to 2.90 × 10-4

50

0.53 (54/102)

2.22 × 10−6 to 1.54 × 10−4

 pS3

Plasmid

Conjugation

1.30 × 10−7

51

0.63 (52/82)

8.24 × 10−8

 pOU1114

DQ115387

Plasmid

Conjugation

4.30 × 10−2

52

0.57 (27/47)

2.47 × 10−2

 pESI

Plasmid

Conjugation

4.00 × 10−6

53

ND

ND

 pWW012

CP022169

Plasmid

Conjugation

1.20 × 10−6

54

ND

ND

Phage

 P22

 

Phage

Lysogenisation

1.57

This work

0.07 (5/70)

1.12 × 10−1

Transposable elements—ICEs

 ICESb1

FN298494.1

Conjugative Tn

Conjugation

1.10 × 10−6

55

0.77 (81/105)

8.49 × 10−7

 SGI3

Conjugative Tn

Conjugation

1.20 × 10−7 to 1.30 × 10−4

56

0.66 (57/86)

7.95 × 10−8 to 8.62 × 10−5

Chromosomal transfer

Generalised transduction

tetA marker HF1d

AE006468.2

Chromosomal DNA

P22-mediated GT

1.52 × 10−4

17

1.00 (41/41)e

1.52 × 10−4

tetA marker HF2

Chromosomal DNA

P22-mediated GT

1.64 × 10−4

17

1.00 (33.5/33.5)

1.64 × 10−4

tetA marker HF3

Chromosomal DNA

P22-mediated GT

3.07 × 10−4

17

1.00 (44/44)

3.07 × 10−4

tetA marker HF4

Chromosomal DNA

P22-mediated GT

3.00 × 10−4

17

1.00 (37/37)

3.00 × 10−4

tetA marker HF5

Chromosomal DNA

P22-mediated GT

3.13 × 10−5

17

1.00 (42/42)

3.13 × 10−5

tetA marker HF6

Chromosomal DNA

P22-mediated GT

2.00 × 10−5

17

1.00 (43/43)

2.00 × 10−5

tetA marker HF7

Chromosomal DNA

P22-mediated GT

1.93 × 10−5

17

1.00 (43/43)

1.93 × 10−5

Lateral transduction

tetA marker HF1

AE006468.2

Chromosomal DNA

P22-mediated LT

2.33 × 10−3

17

0.51 (21.5/42.5)

1.18 × 10−3

tetA marker HF2

Chromosomal DNA

P22-mediated LT

9.27 × 10−3

17

1.00 (33.5/33.5)

9.27 × 10−3

tetA marker HF3

Chromosomal DNA

P22-mediated LT

6.83 × 10−4

17

1.00 (44/44)

6.83 × 10−4

tetA marker HF4

Chromosomal DNA

P22-mediated LT

2.40 × 10−3

17

1.00 (37/37)

2.40 × 10−3

tetA marker HF5

Chromosomal DNA

P22-mediated LT

1.33 × 10−3

17

1.00 (42/42)

1.33 × 10−3

tetA marker HF6

Chromosomal DNA

P22-mediated LT

4.97 × 10−4

17

1.00 (43/43)

4.97 × 10−4

tetA marker HF7

Chromosomal DNA

P22-mediated LT

9.87 × 10−5

17

1.00 (43/43)

9.87 × 10−5

  1. ND not determined.
  2. Source data are provided as a Source Data file.
  3. aIn order to enable comparisons between conjugation and the other modes of horizontal gene transfer, transfer frequency of phage-mediated DNA transfer was analysed as transfer events (TE) per bacterial donor cell at the time of prophage induction: TE per donor cell = Transductant Units (TrU) per ml/1.0 × 108 CFU per ml. TrU per ml data was obtained from the sources indicated. Lysogens were induced at OD600 0.2, which is equivalent to 1.0 × 108 CFU per ml in the donor population.
  4. bCargo capacity rate = Number of accessory ORFs utilisable by the host cell (e.g., virulence factors, AMR genes and HPs)/total ORFs contained within the mobilised DNA sequence. Bracketed values indicate the number of accessories ORFs/total ORFs for each element where sequence data was available for analysis. Phage P22 is proposed to carry five ORFs with lysogenic conversion effects: sieAB and gtrABC.
  5. cRelative frequency of genetic mobility = transfer frequency × cargo capacity rate.
  6. dHF, phage headful (43.8 kb); numbers denote the distance of each tetracycline-resistance marker from the phage chromosomal attachment site in terms of headful units in the direction of phage packaging.
  7. eEstimation of ORFs packaged in HF1 during generalised transduction if packaging terminates in the same location as for HF1 during lateral transduction. No phage genes are expected to be transduced during generalised transduction of the DNA sequence containing the tetracycline-resistance marker, so 100% of the transferred sequence is available for recombination and utilisation by the recipient cell.
  8. fThe total number of accessory ORFs utilisable by the recipient host cell is only a proportion of the total sequence transferred by HF1 because part of the phage genome is also packaged in the first headful during lateral transduction.
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