Ralstonia solanacearum causes bacterial wilt and undergoes spontaneous phenotypic conversion (PC) from its wild-type to an avirulent form. In previous studies, we reported that pre-inoculation of plants with PC mutants suppressed bacterial wilt and Verticillium wilt in eggplants. In addition, we previously revealed bacterial differences in the control effects in eggplant among PC mutants; 8107PC and 8103PC were selected as effective strains for controlling Verticillium wilt and bacterial wilt diseases, respectively. In this study, we investigated the biological control efficiencies of 8107PC inoculation among 19 eggplant cultivars, including 13 commercial cultivars and six rootstock cultivars, to select eggplant cultivars that stably prevent Verticillium wilt using PC mutants. Varietal differences in biological control were confirmed. Additionally, cultivars with a higher potential resistance to Verticillium wilt tended to be more suppressed by the PC mutant, suggesting that cultivar selection is important to achieve effective biocontrol. Furthermore, we found that the biocontrol with 8107PC against Verticillium wilt in grafted eggplant seedlings of Solanum melongena ‘Senryo nigo’ onto S. torvum ‘Tonashimu’ was the most effective rootstock cultivar against Verticillium wilt. The biocontrol was more effective than the non-grafted seedlings inoculated with the PC mutant and the grated seedlings not inoculated with the PC mutant. We also investigated biocontrol by the 8103PC inoculation against bacterial wilt using grafted seedlings (‘Senryo nigo’ as the scion) with ‘Tonashimu’ or S. melongena ‘Daitaro’ as rootstocks. Although ‘Daitaro’ had a low control effect against Verticillium wilt, the grafted seedlings showed a high control effect against bacterial wilt, regardless of the PC mutant inoculation. Conversely, seedlings grafted with ‘Tonashimu’ were vulnerable to bacterial wilt; however, inoculation with the PC mutant completely suppressed the disease. Therefore, this study demonstrated that bacterial wilt and Verticillium wilt could be effectively controlled by inoculation with PC mutants in seedlings grafted with ‘Tonashimu’. The combination of grafting and PC mutant inoculation is expected to be effective for the combined control of Verticillium wilt and bacterial wilt diseases in eggplants.

Ralstonia solanacearum会导致青枯病并经历从野生型到无毒型的自发表型转化 (PC)。在之前的研究中，我们报道了用 PC 突变体预接种植物可以抑制茄子中的青枯病和黄萎病。此外，我们之前揭示了 PC 突变体之间茄子控制效果的细菌差异；8107PC和8103PC分别被选为防治黄萎病和青枯病的有效菌株。本研究考察了19个茄子品种（包括13个商业品种和6个砧木品种）接种8107PC的生防效果，以筛选出稳定防治黄萎病的茄子品种。使用 PC 突变体枯萎。确认了生物控制中的品种差异。此外，对黄萎病具有较高潜在抗性的品种往往更容易受到 PC 突变体的抑制，这表明品种选择对于实现有效的生物防治很重要。此外，我们发现，与8107PC生物防治针对黄萎病枯萎中的嫁接茄子苗茄子“的Senryo NIGO”到S. torvum “Tonashimu”是最有效的对抗砧木品种黄萎病枯萎。生物防治比接种 PC 突变体的未嫁接幼苗和未接种 PC 突变体的磨碎幼苗更有效。我们还研究了通过 8103PC 接种以 'Tonashimu' 或S. melongena 'Daitaro' 作为砧木的嫁接幼苗（'Senryo nigo' 作为接穗）对青枯病的生物防治。尽管“大太郎”对黄萎病的防治效果较低，但无论接种 PC 突变体如何，嫁接的幼苗都对青枯病表现出很高的防治效果。相反，嫁接“Tonashimu”的幼苗易受青枯病影响；然而，接种 PC 突变体完全抑制了这种疾病。因此，本研究表明青枯病和轮枝菌在嫁接'Tonashimu'的幼苗中接种PC突变体可以有效控制枯萎病。接枝和PC突变体接种的组合可望对的组合的控制是有效的黄萎病枯萎并在茄子青枯病疾病。