ANTIBACTERIAL EFFECT OF CECROPINS ON ERWINIA AMYLOVORA/PEAR CELLS INTERACTION/A PRELIMINARY STUDY

The activity of several antibacterial peptides isolated from giant silk moth (Hyalophora cecropia) was tested against E. amylovora. The effect of Cecropin B and its synthetic analogs SB-37 and Shiva-1 on the growth of bacteria population alone or in presence of pear cell suspensions and pear leaf intercellular washing fluids was assayed.
Except for Shiva-1, bactericidal concentrations were consistent with known activities of cecropins (5–15 μM). At these concentrations, cecropins had no toxic effect on pear cells.
Furthermore, in co- culture experiments between pear cells and E. amylovora, the addition of cecropin limited pear cell mortality induced by a virulent strain.
However, antibacterial activity of cecropins was abolished when they were pre-incubated in crude pear intercellular washing fluids.
Gradual degradation of cecropins after 2.5 hours of incubation in crude pear intercellular washing fluids was also demonstrated.
Pear transformation with cecropin genes will be efficient only if continuous secretion of the peptides by plant cells counterbalances their progressive degradation and inhibition by extracellular pear components.

VIII International Workshop on Fire Blight

F. Mourgues, E. Chevreau, M.N. Brisset

antibacterial peptides, Erwinia amylovora, pear

https://doi.org/10.17660/ActaHortic.1999.489.41