INVOLVEMENT OF THE PHENYLPROPANOID PATHWAY IN THE RESISTANCE OF APPLE TO ERWINIA AMYLOVORA

In a former work (Venisse et al., 2002), it was hypothesized that the phenylpropanoid pathway is globally involved in the resistance of apple to Erwinia amylovora. In this study, we further examined the possible role of phenolics in the interaction E. amylovora/apple by looking at their effect on the bacteria in vitro and we also examined the role of the three known Hrp effectors of E. amylovora on the genes of the phenylpropanoid pathway.
We showed that two non glycosylated phenolics of apples can, according to their concentrations i) have a direct antimicrobial action on E. amylovora, ii) decrease the expression of hrp genes of the bacteria and iii) have an antioxidant or a prooxidant effect.
We also showed that the three known Hrp effectors of E. amylovora can repress, alone or in combination, some genes of the phenylpropanoid pathway in a susceptible genotype.
These results tend to confirm the preliminary hypothesis stating that the phenylpropanoid pathway is one of the mechanisms involved in the resistance of apple to fire blight.

X International Workshop on Fire Blight

I. Pontais, J.P. Paulin, M.N. Brisset

Maloideae, fire blight, plant defense, phenolic compounds, Hrp effectors

https://doi.org/10.17660/ActaHortic.2006.704.75