*2.1. Bacterial Strains and In Vitro Plant Treatments*

### 2.1.1. Bacterial Cultures

*Bacillus amyloliquefaciens* GB03 (originally described as *Bacillus subtilis* GB03) [40] strain was grown on LB (Luria-Bertani) medium for routine use and maintained in nutrient broth with 15% glycerol at −80 ◦C for storage. The bacterial culture was grown overnight at 30 ◦C and centrifuged at 120, washed twice in 0.9% NaCl by Eppendorf centrifugation (4300× *g*, 10 min, 4 ◦C), re-suspended in sterile water, and adjusted to a final concentration of ~10<sup>9</sup> CFU/ mL for use as an inoculum.
