Potential of bulb-associated bacteria for biocontrol of hyacinth soft rot caused by Dickeya zeae.
OBJECTIVE
Dickeya zeae is a pectinolytic bacterium responsible for soft rot disease in flower bulb crops. In this study, the possibility of controlling soft rot disease in hyacinth by using antagonistic bacteria isolated from hyacinth bulbs was explored.


RESULTS
Bacterial isolates with potential for biocontrol were selected on the basis of antibiosis against D. zeae, siderophore production, and the N-acyl homoserine lactones (AHLs)-inactivation. In in vitro assays, 35 out of 565 hyacinth-associated bacterial isolates produced antimicrobial substances against D. zeae, whereas 20 degraded AHLs, and 35 produced siderophores. Isolates of interest were identified by 16S rDNA sequence analysis and reaction in BIOLOG tests. Twenty-six isolates that differed in characteristics were selected for pathogenicity testing on hyacinth cultivars, Pink Pearl and Carnegie. Two strains identified as Rahnella aquatilis and one as Erwinia persicinus significantly reduced tissue maceration caused by D. zeae 2019 on hyacinth bulbs, but not on leaves.


CONCLUSIONS
Hyacinth bulbs harbour bacteria belonging to different taxonomic groups that are antagonistic to D. zeae, and some can attenuate decay of bulb tissue.


CONCLUSIONS
Selected hyacinth-associated bacterial isolates have potential for control of soft rot disease caused by D. zeae in hyacinth bulb production.
Jafra
S
S
Plant Research International, Wageningen, The Netherlands. jafra@biotech.ug.gda.pl
Przysowa
J
J
Gwizdek-Wiśniewska
A
A
van der Wolf
J M
JM
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D000898:Antibiosis / Q000235:genetics; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases; D031806:Eichhornia / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000302:isolation & purification; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017262:Siderophores / Q000032:analysis
D000900:Anti-Bacterial Agents; D012336:RNA, Ribosomal, 16S; D017262:Siderophores; C088386:homoserine lactone; D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase; D015107:4-Butyrolactone