title: Role of Pantoea agglomerans in opportunistic bacterial seed and boll rot of cotton (Gossypium hirsutum) grown in the field.
abstract: OBJECTIVE
  To investigate the aetiology of seed and boll rot of cotton grown in South Carolina (SC).
  
  
  RESULTS
  Bacteria were isolated from diseased locules of cotton bolls collected in a field in SC, USA and tested for the ability to cause comparable disease symptoms in greenhouse grown cotton fruit. Spontaneously generated rifampicin-resistant (Rif(r)) mutants of the isolates were used in confirmatory pathogenicity tests. Resistance to the antibiotic was both stable and effective in differentiating between an inoculated Rif(r) strain, rifampicin-sensitive contaminants and/or endophytes. A series of inoculation methods was tested at various boll developmental stages and at different fruiting nodes on the plant. Field disease symptoms were reproduced by inoculating bolls at 2 weeks postanthesis with bacterial suspensions ranging from 10(3) to 10(6) CFU ml(-1). Pathogenic isolates were categorized as Pantoea agglomerans on the basis of phenotype testing, fatty acid profiling (similarity index = 0.94), and 16s ribosomal DNA sequence analysis (99% nucleotide identity).
  
  
  CONCLUSIONS
  Pantoea agglomerans isolates from field-collected immature, diseased cotton caused comparable infection symptoms in greenhouse produced cotton fruit.
  
  
  CONCLUSIONS
  In 1999, significant yield losses in SC cotton resulted from a previously unobserved seed and boll rot that has since been reported in other southeastern states. This study demonstrated a role of P. agglomerans in producing opportunistic bacterial seed and boll rot of cotton.
authors.affiliation: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Cotton Pathology Research Unit (CPRU), College Station, TX 77845, USA. gmedrano@cpru.usda.gov
authors.forename: E G
authors.initials: EG
authors.lastname: Medrano
authors.forename: A A
authors.initials: AA
authors.lastname: Bell
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005227:Fatty Acids / Q000032:analysis; D003368:Gossypium / Q000382:microbiology*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D020636:Pantoea / Q000187:drug effects / Q000302:isolation & purification* / Q000472:pathogenicity; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D012293:Rifampin / Q000494:pharmacology; D013022:South Carolina
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012293:Rifampin