Journal article
Lipopeptide production in Pseudomonas sp strain DSS73 is regulated by components of sugar beet seed exudate via the gac two-component regulatory system
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.
Language: | English |
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Publisher: | American Society for Microbiology |
Year: | 2002 |
Pages: | 4509-4516 |
ISSN: | 10985336 and 00992240 |
Types: | Journal article |
DOI: | 10.1128/AEM.68.9.4509-4516.2002 |
ORCIDs: | 0000-0001-9281-2249 , 0000-0001-7354-0188 and Molin, Søren |