4.6. Colonization Capacity of K165 and F2 in Vines

The trunk colonization capacity of F2 and K165 was evaluated by following the methodology of Pch isolation, at the end of the in planta experiment (90 days after Pch inoculation). The xylem chips were placed onto PDA plates amended with hygromycin B (75 μg mL⁻¹) and rifampicin (100 μg mL⁻¹) and placed at 28 °C in the dark for 3 days. To estimate the rhizosphere K165 population, 0.5 g rhizosphere soil was collected and shaken for 45 min in 50 mM phosphate buffer (pH 7.02) containing Tween 20 (0.02%). The suspension was plated onto PDA supplemented with rifampicin (100 μg mL⁻¹). After incubation at 30 °C for 48 h, the number of K165 cfu g⁻¹ of rhizosphere soil was determined.