Isolation and Cultivation of Pseudomonas syringae

The Pseudomonas syringae pv. actinidiae strain CRA-FRU 8.43 (Psa 3, also referred to as Psa V or Biovar 3) isolated in Lazio, Italy, in 2008, and obtained from the Culture Collection of the Centro di Ricerca per la Frutticoltura (Rome, Italy) [28 (link),29 (link)] was used. The bacterial strain was grown in Luria–Bertani Agar (LA, Liofilchem, Roseto TE, Italy) at 25 °C for 48 h and then kept at 4 °C. Before each assay, a colony of the bacteria was aseptically inoculated in 30 mL of Tryptic Soy Broth (TSB, Liofilchem, Roseto TE, Italy) and grown aerobically for 24 h at 25 °C under stirring (120 rpm). The viable cell density was approximately 10⁸ colony-forming units per mL (CFU mL⁻¹).