MECHANISMS UNDERLYING DISEASE AND RESISTANCE IN HOST PLANTS OF FIRE BLIGHT

Most pathogenicity determinants of Erwinia amylovora are identified but molecular mechanisms leading to susceptibility to disease, or resistance, are not yet understood.
To address this question, we undertook a comparison of molecular responses of two genotypes of apple (known for their contrasting susceptibility to fire blight) challenged with E. amylovora, an hrp secretion mutant of this bacteria or the incompatible pathogen Pseudomonas syringae pv. tabaci. Results showed three types of response : (i) some mechanisms are elicited in both susceptible and resistant genotypes by E. amylovora and P. s. pv. tabaci with similar kinetics, (ii) others are specifically repressed or induced by E. amylovora in its susceptible host, (iii) some mechanisms are induced in incompatible situations only, i.e. E. amylovora/resistant genotype or P. s. pv. tabaci/susceptible and resistant genotypes.
All these events (induction and repression) seemed to be linked to a functional Hrp apparatus in the bacteria.

IX International Workshop on Fire Blight

J.S. Venisse, J.P. Paulin, M.N. Brisset

Erwinia amylovora, defense, compatibility, incompatibility, hrp mutant

https://doi.org/10.17660/ActaHortic.2002.590.72