We present here a brief review of plant mechanisms which have been studied in relation with Erwinia amylovora. These mechanisms concern exclusively host plant of fire blight and may act either positively or negatively on the bacteria. They may therefore be involved in the susceptibility or the resistance of plant tissues, either at the genetic or at the ontogenic level. Preformed plant mechanisms are first presented and include host attractivity, iron availability, water availability, preformed antibacterial compounds, bacterial immobilization. Then induced plant mechanisms follow with production of reactive oxygen species, synthesis of PR-proteins and stimulation of the phenylpropanoid pathway.