Sterilization and Germination of Cucumber Seeds

Cucumis sativus ’Jinyan No.4’ was used in this experiment. Before germination, seeds were treated with 10% (w/v) trisodium phosphate for 30 min to sterilize, followed by washing with sterile water several times, and soaking in sterile water for approximately 3 h. Finally, the sterilized seeds were placed on a Petri dish covered with wet Whatman paper and cultivated for 3–4 days at 28 °C in the dark for the next experiment when the lateral roots grew out.
Pluronic F-127 (PF-127) is a copolymer of propylene oxide and ethylene oxide, with negligible toxicity to nematodes or plant tissues. The nematodes suspended in PF-127 gel can move freely in three-dimensional space, which is more similar to their movement in the soil. Therefore, using this system to simulate the natural soil environment can more effectively assess host–pathogen interactions [54 (link)]. Based on these properties, the assay used PF-127 as the medium for nematode infection. PF-127 was purchased from Sigma-Aldrich (USA). The preparation was performed according to the protocol of Xing et al. [55 ]. In brief, 23 g of Pluronic F-127 powder was added to 80 mL of pre-cooled sterile water dissolved under stirring at 4 °C for 24 h, and then stored at 15 °C for later experimental use.