ISHS Acta Horticulturae 273: V International Workshop on Fireblight
TRANSPOSON MUTAGENESIS OF ERWINIA AMYLOVORA |
| Authors: | P. Bellemann, N. Jahn, R. Theiler, K. Geider |
| Abstract:
Transposon Tn5 on a mobilizable Co1E1 plasmid, on a bacteriophage fd derivative and on a Ti-plasmid, which was derepressed for bacterial plasmid transfer, were used to create mutants of Erwinia amylovora. In a strain, which is unable to propagate Co1E1 plasmids, not only transposon Tn5 but also transposon Tn4431 with a promotorless lux operon was inserted into the E. amylovora genome. The latter type of mutagenesis yielded bioluminescent strains, which were dependent on the presence of pear cells or plant cell extracts for light production. Bacterial spread on a pear cell lawn was monitored by bioluminescence. Staining of plant cells for viability indicated that only living cells support propagation of E. amylovora. The insertion site of the Tn5 mutants were mapped into seven classes and the EcoRI DNA fragments were cloned. Mutants from different classes could complement each other to produce virulence symtomes on pear slices in contrast to strains belonging to one class. One mutant was auxotrophic. The other mutants were prototrophic and altered in synthesis of extracellular polysaccharides. | |
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