Transduction of Escherichia coli by bacteriophage P1 in soil

Abstract

Transduction of Escherichia coli W3110(R702) and J53(RP4) (104 to 105 CFU/g of soil) by lysates of temperature-sensitive specialized transducing derivatives of bacteriophage P1 (104 to 105 PFU/g of soil) (P1 Cm cts, containing the resistance gene for chloramphenicol, or P1 Cm cts::TnSOI, containing the resistance genes for chloramphenicol and mercury [Hg]) occurred in soil amended with montmorillonite or kaolinite and adjusted to a-33-kPa water tension. In nonsterile soil, survival of introduced E. coli and the numbers of E. coli transductants resistant to chloramphenicol or Hg were independent of the clay amendment. The numbers of added E. coli increased more when bacteria were added in Luria broth amended with Ca and Mg (LCB) than when they were added in saline, and E. coli transductants were approximately 1 order of magnitude higher in LCB; however, the same proportion of E. coli was transduced with both types of inoculum. In sterile soil, total and transduced E. coli and P1 increased by 3 to 4 logs, which was followed by a plateau when they were inoculated in LCB and a gradual decrease when they were inoculated in saline. Transduction appeared to occur primarily in the first few days after addition of P1 to soil. The transfer of Hg or chloramphenicol resistance from lysogenic to nonlysogenic E. coli by phage P1 occurred in both sterile and nonsterile soils. On the basis of heat-induced lysis and phenotype, as well as hybridization with a DNA probe in some studies, the transductants appeared to be the E. coli that was added. Transduction of indigenous soil bacteria was not unequivocally demonstrated. The survival of P1, E. coli hosts, and transductants for at least 28 days in nonsterile soil indicated the potential for genetic transfer via transduction in soil.

On the track of natural transformation in soil

“…Transduction is a phage mediated transfer mechanism thought to promote transfer between only closely related microorganisms [1]. Results indicate that transduction can occur in soil when both recipient cells and phage particles are present [10,11]. However, there are no reports of transduction of indigenous bacteria making transfer of recombinant genes via transduction from inoculated microbial cells to the indigenous microflora in natural conditions.…”

Persistence and stability of genetically manipulated derivatives of Enterobacter agglomerans in soil microcosms

“…However this transposable element can generate rearrangements in the genome of host cells [24] and so alter their characteristics. On the other hand, since all kinds of genetic exchange have been shown to occur in the environment [18,[25][26][27][28][29][30], one cannot exclude the possibility of transfer of Tn5 to some representatives of the natural communities. There is little information available about the possible consequences of the introduction of large amounts of bacteria labeled with transposable elements into soil [23].…”

Phage-host interactions in soil

“…Lysogenic conversion can also confer pathogenicity, for example the prophage of lysogenic Corynebacterium diptheriae strains encodes the toxins enabling establishment of bacterial infection in hosts [7]. Engineered phages containing antibiotic and heavy metal resistance determinants [40,41,[44][45][46] may be advantageous to lysogenic hosts in selective environments [42].…”

“…Lysogenic conversion as shown by lysogenic infections of inoculated hosts in soil by temperate phages containing genetic markers [40][41][42]45,46] is likely to be a far more frequent occurrence in soil in comparison to transduction. This is because all of the daughter progeny of a lysing cell will contain the genetic information to be expressed by the prophages of subsequent lysogenic infections.…”