Bacillus subtilis 1JN2 can serve as an effective biocontrol agent against Ralstonia wilt on tomato, but the efficiency of control depends on the levels of heavy metals in the rhizosphere soil. Here, we investigated how the heavy metal Cd²⁺ affects the biocontrol efficacy of B.subtilis 1JN2 on Ralstonia wilt. We found that low Cd²⁺ content of 2 mM or lower had no effects on the biofilm formation of 1JN2, while media containing 3 mM or higher Cd²⁺ levels inhibited biofilm formation. Interestingly, high concentration of Cd²⁺ (5 mM) showed inhibition of B.subtilis 1JN2 cell growth. We next tested the effects of Cd²⁺ on the colonization of 1JN2 by supplementing artificial Cd²⁺ in the tomato rhizosphere in a greenhouse setting. We found that 3 mM Cd²⁺ in the tomato rhizosphere inhibited the colonization of B.subtilis 1JN2, Only 10³ CFU/mL 1JN2 was detected one week post treated with 10⁷ CFU/mL but 10⁵ CFU/mL could be detected without Cd²⁺ in the soil. The presence of Cd²⁺ had no effect on the colonization of Ralstonia solanacearum on tomato, but the biocontrol efficacy against Ralstonia wilt by 1JN2 decreased 54.2% when the soil contained 3 mM Cd²⁺ compared to the control without Cd²⁺. Taken together, we found that the failure of biofilm formation of Bacillus subtilis 1JN2 that affected by Cd²⁺ lead to the decrease of its biocontrol efficacy against Ralstonia wilt on tomato.

枯草芽孢杆菌1JN2可以作为针对有效生物防治剂青枯对番茄枯萎病，但控制的效率取决于重金属在根际土壤的水平。在这里，我们调查了重金属镉如何²⁺影响的生物防治效果枯草杆菌1JN2对青枯病枯萎。我们发现2 mM或更低的低Cd ²⁺含量对1JN2的生物膜形成没有影响，而包含3 mM或更高Cd ²⁺水平的培养基则抑制了生物膜的形成。有趣的是，高浓度的Cd ²⁺（5 mM）表现出对枯草芽孢杆菌1JN2细胞生长的抑制作用。接下来我们测试了镉的影响²⁺在1JN2的通过补充人工Cd中的定植²⁺在番茄在温室环境根际。我们发现，3mM的镉²⁺在番茄根际抑制的定植枯草杆菌1JN2，只有10 ³  CFU / mL的1JN2检测后一周用10处理⁷  CFU / mL的但10 ⁵  CFU / mL的可以在没有被检测到土壤中的镉²⁺。镉的存在²⁺对的定殖没有影响青枯雷尔氏菌对番茄，而是针对生物防治功效青枯当土壤含有3mM的镉萎通过1JN2下降54.2％²⁺与不含Cd ²⁺的对照相比。总之，我们发现，生物膜形成的失败枯草芽孢杆菌1JN2，受镉²⁺导致针对其生物防治效果的减少青枯病番茄枯萎。