Lipopeptide production in Pseudomonas sp. strain DSS73 is regulated by components of sugar beet seed exudate via the Gac two-component regulatory system

TY - JOUR

T1 - Lipopeptide production in Pseudomonas sp. strain DSS73 is regulated by components of sugar beet seed exudate via the Gac two-component regulatory system

AU - Koch, Birgit

AU - Nielsen, Tommy H

AU - Sørensen, Dan

AU - Andersen, Jens Bo

AU - Christophersen, Carsten

AU - Molin, Søren

AU - Givskov, Michael

AU - Sørensen, Jan

AU - Nybroe, Ole

N1 - Keywords: Bacterial Proteins; Beta vulgaris; DNA Transposable Elements; Mutagenesis; Peptide Synthases; Peptides, Cyclic; Phenotype; Plant Extracts; Pseudomonas; Seeds; Transcription Factors

PY - 2002

Y1 - 2002

N2 - Pseudomonas sp. strain DSS73 isolated from the sugar beet rhizosphere produces the cyclic lipopeptide amphisin, which inhibits the growth of plant-pathogenic fungi. By Tn5::luxAB mutagenesis, we obtained two nonproducing mutant strains, DSS73-15C2 and DSS73-12H8. The gene interrupted by the transposon in strain DSS73-15C2 (amsY) encoded a protein with homology to peptide synthetases that was designated amphisin synthetase. DSS73-12H8 carried the transposon in a regulatory gene encoding a protein with homology to the sensor kinase GacS. Growth of strain DSS73-15C2 (amsY) was impaired during the transition to stationary phase in a minimal medium amended with an exudate of sugar beet seeds. This growth phenotype could be complemented by purified amphisin. Seed exudate further induced expression of bioluminescence from the amsY::luxAB reporter during the transition to stationary phase. This agreed with an increase in amphisin production by the DSS73 wild-type strain during early stationary phase. Amphisin synthesis in DSS73 was strictly dependent on GacS, and even induction by seed exudate depended on a functional gacS locus. Hence, a signal triggering the GacS/GacA two-component system appeared to be present in the seed exudate.

AB - Pseudomonas sp. strain DSS73 isolated from the sugar beet rhizosphere produces the cyclic lipopeptide amphisin, which inhibits the growth of plant-pathogenic fungi. By Tn5::luxAB mutagenesis, we obtained two nonproducing mutant strains, DSS73-15C2 and DSS73-12H8. The gene interrupted by the transposon in strain DSS73-15C2 (amsY) encoded a protein with homology to peptide synthetases that was designated amphisin synthetase. DSS73-12H8 carried the transposon in a regulatory gene encoding a protein with homology to the sensor kinase GacS. Growth of strain DSS73-15C2 (amsY) was impaired during the transition to stationary phase in a minimal medium amended with an exudate of sugar beet seeds. This growth phenotype could be complemented by purified amphisin. Seed exudate further induced expression of bioluminescence from the amsY::luxAB reporter during the transition to stationary phase. This agreed with an increase in amphisin production by the DSS73 wild-type strain during early stationary phase. Amphisin synthesis in DSS73 was strictly dependent on GacS, and even induction by seed exudate depended on a functional gacS locus. Hence, a signal triggering the GacS/GacA two-component system appeared to be present in the seed exudate.

M3 - Journal article

SN - 0099-2240

VL - 68

SP - 4509

EP - 4516

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

IS - 9

ER -