An improved Escherichia coli donor strain for diparental mating

FEMS Microbiol Lett. 2009 May;294(2):127-32. doi: 10.1111/j.1574-6968.2009.01556.x.


We present a new method for diparental mating with the outstanding advantage that counterselection of the Escherichia coli donor strain is not required. This improved method uses a new donor strain, E. coli ST18, a hemA deletion mutant defective in tetrapyrrole biosynthesis. The hemA mutation can be complemented by addition of 5-aminolevulinic acid. Therefore, counterselection is carried out only using standard media and growth conditions optimal for the recipient strain. Consequently, recipient strains are isolated in a significantly shorter period.

Publication types

  • Letter
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Oxidoreductases / deficiency
  • Aminolevulinic Acid / metabolism
  • Conjugation, Genetic*
  • DNA Transposable Elements
  • Escherichia coli / genetics*
  • Gene Transfer Techniques*
  • Mutagenesis
  • Pseudomonas / genetics
  • Rhodobacter / genetics


  • DNA Transposable Elements
  • Aminolevulinic Acid
  • Aldehyde Oxidoreductases
  • glutamyl tRNA reductase