2.1.2. Plant Micropropagation

The *M. piperita* plant is a commercially cultivated crop grown in the Traslasierra valley (Córdoba province, Argentina). Young shoots from peppermint were surface-disinfected and micropropagated, as previously described by Santoro et al. [26].

#### 2.1.3. In Vitro Exposure to mVOCs

Single nodes from aseptically cultured plantlets were planted in sterilized glass jars (250 mL) containing 50 mL MS (Murashige and Skoog) solid media with 0.8% (*w*/*v*) agar and 3% (*w*/*v*) sucrose. Then, a small (10 mL) glass vial containing ca. 3 mL of Hoagland media with 0.8% (*w*/*v*) agar and 3% (*w*/*v*) sucrose was introduced into each jar. The small vial was inoculated with GB03 (50 μL), which served as the source of bacterial volatiles, with sterile water used in the control. Plants were exposed to mVOCs without having any physical contact with the rhizobacteria. Jars containing plants and bacteria were covered with aluminum foil, sealed with parafilm to avoid contamination, and placed in a growth chamber under controlled conditions (16/8-h light/dark cycle), temperature (22 ± 2 ◦C) and relative humidity (~70%). After 30 days, all plants were collected [38].
