title: Genome shuffling enhances biocontrol abilities of Streptomyces strains against two potato pathogens.
abstract: OBJECTIVE
  To employ the genome shuffling technique for improving the phenotype of a biocontrol control agent of the genus Streptomyces.
  
  
  RESULTS
  Two rounds of genome shuffling (GS) were carried out with Streptomyces melanosporofaciens EF-76, a geldanamycin producer. Six fusants that showed optimized in vitro antagonistic activity against Streptomyces scabies or Phytophthora infestans, two important pathogens of potato crops, were selected. All selected fusants retained the capacity to produce geldanamycin, but none overproduced this antibiotic. The higher antagonism ability appeared to result from a diversification of secreted metabolites. Seven or eight metabolites were detected in the HPLC profiles of parental strains, whereas 12-15 were detected in fusant strains. Biocontrol assays revealed that four of six fusants protected tubers more efficiently than parental strains.
  
  
  CONCLUSIONS
  GS emerged as an elegant and rapid tool to optimize the antagonistic ability of Streptomyces strains. Optimization of the in vitro antagonistic activity against plant pathogens appears to be an effective approach to select for improved biocontrol agents. The enhanced phenotype did not depend on an overproduction of a specific antibiotic but rather on the secretion of a wider variety of secondary metabolites.
  
  
  CONCLUSIONS
  Improved capacities of a biocontrol agent compensate for the lack of efficient chemical control of potato scab.
authors.affiliation: Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Clermont
authors.forename: S
authors.initials: S
authors.lastname: Lerat
authors.forename: C
authors.initials: C
authors.lastname: Beaulieu
mesh_terms: D000898:Antibiosis; D016227:Benzoquinones / Q000378:metabolism; D061046:Biological Control Agents; D032621:DNA Shuffling; D004269:DNA, Bacterial / Q000235:genetics; D016680:Genome, Bacterial; D047029:Lactams, Macrocyclic / Q000378:metabolism; D055750:Phytophthora infestans / Q000472:pathogenicity; D010935:Plant Diseases / Q000382:microbiology; D011198:Solanum tuberosum / Q000382:microbiology*; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D016227:Benzoquinones; D061046:Biological Control Agents; D004269:DNA, Bacterial; D047029:Lactams, Macrocyclic; C001277:geldanamycin