Ralstonia solanacearum causes bacterial wilt and undergoes spontaneous phenotypic conversion (PC) from its wild-type form to non-pathogenic form. We previously reported that the pre-inoculation of PC mutants in Solanum plants suppressed bacterial wilt. In the present study, we clarified the inoculation method of PC mutants and PC mutant strains for effective control the eggplant Verticillium wilt caused by Verticillium dahliae, a soil-borne fungal plant pathogen. We first investigated three different methods for pre-inoculating PC mutants in the five-leaf-stage seedlings of eggplant: Method A involved soaking plant roots in the PC mutant suspension immediately before challenge-inoculation with V. dahliae; Method B involved irrigation with the PC mutant suspension in pots at 7 days before challenge-inoculation with the pathogen; and Method C involved soaking plant roots in the PC mutant suspension at 3 weeks before challenge-inoculation with the pathogen. The highest biological control was achieved with Method A. To quickly and easily select effective PC mutants for biological control of Verticillium wilt in a growth chamber, a simplified evaluation method based on Method A was applied using the young (two-leaf-stage) seedlings of eggplant. Furthermore, we investigated the biological control efficacies of 27 PC mutants against Verticillium wilt in eggplants using the simplified evaluation method in vivo, and growth inhibition of V. dahliae by PC mutants in vitro. However, no relationship existed between the biological control and growth inhibition of V. dahliae, suggesting that it is unlikely to be involved as the main factor affecting the biological control by PC mutants. Three PC mutants, 8345PC, 8109PC, and 8107PC, which showed high biological control efficacies in the simplified evaluation method (64.6%, 66.0%, and 68.9%, respectively), were evaluated for their biological control using five-leaf-stage eggplant seedlings in greenhouse test. Among these three mutants, the 8107PC strain showed the highest biological control of 43.3% and was selected as the most effective PC mutant for suppressing Verticillium wilt in eggplant. Thus, the use of PC mutants is expected to be effective in the control of Verticillium wilt in eggplant.

青枯雷尔氏菌引起细菌枯萎，并经历了从野生型到非致病性的自发表型转化（PC）。我们以前曾报道过，茄属植物中PC突变体的预接种抑制了细菌的枯萎。在本研究中，我们阐明了PC突变体和PC突变体菌株的接种方法，可有效控制由土壤传播的真菌植物病原体大黄萎病菌引起的茄子黄萎病。我们首先研究了三种在茄子五叶期幼苗中预接种PC突变体的不同方法：方法A涉及在用V. dahliae挑战接种之前立即将植物根部浸泡在PC突变体悬浮液中。; 方法B涉及在用病原体激发接种前7天用PC突变体悬浮液在盆中灌溉。方法C涉及在用病原菌攻击前3周将植物根部浸泡在PC突变体悬浮液中。用方法A实现了最高的生物防治。为快速，轻松地选择有效的PC突变体对生长室中的黄萎病进行生物防治，使用了基于方法A的简化评估方法，该方法使用了幼苗（两叶期）茄子 此外，我们在体内使用简化的评估方法调查了27种PC突变体对茄子中黄萎病的生物防治效果，以及对大丽花的生长抑制作用。通过PC突变体外。然而，大麦弧菌的生物学控制与生长抑制之间不存在关系，这表明它不可能作为影响PC突变体生物学控制的主要因素。使用五叶阶段茄子苗评估了三个PC突变体8345PC，8109PC和8107PC，它们在简化评估方法中表现出较高的生物防治效果（分别为64.6％，66.0％和68.9％）。在温室测试中。在这三个突变体中，8107PC菌株显示出最高的43.3％的生物学控制，被选为抑制黄萎病最有效的PC突变体茄子枯萎。因此，预期使用PC突变体可有效控制茄子中的黄萎病。