金属固定化细菌在蔬菜中金属积累中起关键作用。然而,关于细菌诱导的降低蔬菜中金属利用率和吸收的机制知之甚少。在这项研究中,金属固定化黄绿假单胞菌WRS8对植物生物量的影响,两个香菜(CoriandrumsativumL.)品种中Cd和Pb的利用率和吸收,并对污染土壤中的细菌群落结构进行了研究。菌株WRS8使两个香菜品种的生物量增加了25-48%,可食用组织中的Cd和Pb含量减少了40-59%,根际土壤中的有效Cd和Pb含量减少了11.1-15.2%,与对照组相比。菌株WRS8显着增加了鞘氨醇单胞菌优势种群的pH值和相对丰度,假单胞菌,盖勒莱斯,链霉菌,Frankiales,缓生根瘤菌,和Luteimonas,而菌株WRS8显着降低了双子科优势种群的相对丰度,硝基螺旋体,Haliangium,拟芽孢杆菌,Massilia,Bryobacter,以及Rokubacteriales和罕见的肠道细菌种群,罗斯布里亚,Luteibacter,和根际土壤中的Planifilum,与对照组相比。在有效金属浓度和假单胞菌的丰度之间观察到显着的负相关,Luteimonas,Frankiales,和Planifilum。这些结果表明,菌株WRS8可以影响参与金属固定化的优势和稀有细菌种群的丰度,导致pH值增加,金属的有效性和受污染土壤中蔬菜的吸收减少。
Metal-immobilizing bacteria play a critical role in metal accumulation in vegetables. However, little is known concerning the mechanisms involved in bacteria-induced reduced metal availability and uptake in vegetables. In this study, the impacts of metal-immobilizing Pseudomonas taiwanensis WRS8 on the plant biomass, Cd and Pb availability and uptake in two coriander (Coriandrum sativum L.) cultivars, and bacterial community structure were investigated in the polluted soil. Strain WRS8 increased the biomass of two coriander cultivars by 25-48% and reduced Cd and Pb contents in the edible tissues by 40-59% and available Cd and Pb contents in the rhizosphere soils by 11.1-15.2%, compared with the controls. Strain WRS8 significantly increased the pH values and relative abundances of the dominant populations of Sphingomonas, Pseudomonas, Gaiellales, Streptomyces, Frankiales, Bradyrhizobium, and Luteimonas, while strain WRS8 significantly decreased the relative abundances of the dominant populations of Gemmatimonadaceae, Nitrospira, Haliangium, Paenibacillus, Massilia, Bryobacter, and Rokubacteriales and the rare bacterial populations of Enterorhabdus, Roseburia, Luteibacter, and Planifilum in the rhizosphere soils, compared with the controls. Significantly negative correlations were observed between the available metal concentrations and the abundances of Pseudomonas, Luteimonas, Frankiales, and Planifilum. These results implied that strain WRS8 could affect the abundances of the dominant and rare bacterial populations involved in metal immobilization, resulting in increased pH values and decreased metal availability and uptake in the vegetables in the contaminated soil.