CONSTITUTIVE EXPRESSION OF ERWINIA AMYLOVORA HRPN IN TRANSGENIC PEARS REDUCES FIRE BLIGHT SUSCEPTIBILITY

The rapid and effective activation of disease resistance responses is essential for plant defense against pathogen attack.
These responses are initiated when pathogen-derived molecules are recognized by the host.
In order to improve fire blight resistance in pear, we generated transgenic pears expressing the harpin effector from Erwinia amylovora (HrpN_Ea) under the control of the constitutive promoter CaMV35S. Seventeen transgenic diploid clones of the very susceptible cultivar Passe Crassane were obtained and analyzed by RT-PCR, western blot and ELISA. In vitro tests for fire blight resistance were performed by inoculation with a virulent strain of E. amylovora (CFBP 1430, 10⁶ and 10⁷ cfu/ml). Most transgenic clones displayed significant reduction of susceptibility to fire blight in vitro when inoculated by E. amylovora, which could be related to their degree of expression of the transgene hrpN_ea. These results indicate that ectopic expression of a bacterial effector such as HrpN_Ea is a promising way to improve pear resistance to fire blight.

X International Workshop on Fire Blight

E. Chevreau, M. Malnoy, M. Boccara

Pyrus communis L., Erwinia amylovora, transgenic, resistance, Harpin N_ea

https://doi.org/10.17660/ActaHortic.2006.704.85