01525naa a2200229 a 450000100080000000500110000800800410001910000210006024501380008126000090021930000140022852008320024265000240107465000160109865000090111465000140112365000150113765000140115265000090116670000240117577300960119916210431999-05-27       1994    bl ---       0--  u    #d1 aVAN ELSAS, J. D.  aUse of environmentally-triggered promoters for specific differential gene expression in bacterial inoculants in soil and rhizosphere.  c1994  ap.238-244  aDifferent factors in soil and rhizosphere which affect bacterial activity are discussed in the light of the complexity of these two ecosystems. The use of transposon-based promoter probe insertions to obtain environmentally induced expression of beneficial genes for use in biological control as well as impairment of bacterial survival is described. Pseudomonas fluorescens and P. cepacia promoters reacting to wheat root exudates have been identified. One insertion mutant of P. fluorescens was specifically induced by proline, whereas the P. cepacia mutant was induced by leucine. In soil microcosms, induction of gene expression was shown to be rhizospheres of wheat, maize and grass, but not of clover. Possibilities for using the promoters for the induction of expression of beneficial genes (e.g. cryIVB) are considered.  ainoculation methods  arhizosphere  asoil  aBactéria  aInoculante  aRizosfera  aSolo1 aVAN OVERBEEK, L. S.  tImproving plant productivity with rhizosphere bacteria. Australia: CSIRO, p. 238-244, 1994.