*4.2. Isolation of Endophytic Bacteria from Grapevine Shoot Xylem*

Grapevine shoots were collected on 9 December 2019. The surface of the shoots was sterilized with 0.1% (*v*/*v*) sodium hypochlorite solution for 3 min at room temperature. Bark and epidermal tissue were peeled off from the shoots using a knife sterilized with 70% ethanol. Xylem was shaved using a grater sterilized with 70% ethanol. One gram of shaved xylem was placed in a sterilized 100 mL flask containing 40 mL of phosphate buffer solution (pH 7.4). After shaking at 130 rpm for 3 h at 25 ◦C, the phosphate buffer solution with shaved xylem was filtered through sterilized cotton gauze. One hundred microliters of filtrate was plated on SCD, Luria–Bertani broth, and potato dextrose broth agar (PDA) plates, and the plates were incubated at 25 ◦C for 3 d. Bacterial isolates that grew on the plates were used in the in vitro bioassay.
