*4.3. E. amylovora In Vitro Experiments*

*E. amylovora* strain Ea273 was obtained from American Type Culture Collection (ATCC number 49946). The strain was stocked at −80 ◦C in LB plus glycerol 25% (*v*/*v*) and precultured in LB broth at 30 ◦C under agitation (150 rpm) in the absence of light. The growth was monitored by turbidimetric measurements (OD600).

Seed cultures in the late exponential phase of growth [OD<sup>600</sup> of 4.5–4.8] were used to inoculate 100 mL of LB medium (initial OD<sup>600</sup> of 0.1), to evaluate the effect of the light quality on the growth. The inoculated broth was grown in 500-mL Erlenmeyer flasks in an INFORS HT Multitron incubator equipped with monochromatic LED lights of the appropriate spectral wavelength. The growth was carried out under constant temperature (30 ◦C) and agitation (180 rpm), in continuous light or darkness, and was monitored over a 24-h period. All experiments were carried out in triplicate and included three biological and two technical replicates.
