Ma Ying, Oliveira Rui S, Nai Fengjiao, Rajkumar Mani, Luo Yongming, Rocha Inês, Freitas Helena
Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal; Research Centre on Health and Environment, School of Allied Health Sciences, Polytechnic Institute of Porto, Rua Valente Perfeito, 322, 4400-330 Vila Nova de Gaia, Portugal.
J Environ Manage. 2015 Jun 1;156:62-9. doi: 10.1016/j.jenvman.2015.03.024. Epub 2015 Mar 19.
Endophyte-assisted phytoremediation has recently been suggested as a successful approach for ecological restoration of metal contaminated soils, however little information is available on the influence of endophytic bacteria on the phytoextraction capacity of metal hyperaccumulating plants in multi-metal polluted soils. The aims of our study were to isolate and characterize metal-resistant and 1-aminocyclopropane-1-carboxylate (ACC) utilizing endophytic bacteria from tissues of the newly discovered Zn/Cd hyperaccumulator Sedum plumbizincicola and to examine if these endophytic bacterial strains could improve the efficiency of phytoextraction of multi-metal contaminated soils. Among a collection of 42 metal resistant bacterial strains isolated from the tissues of S. plumbizincicola grown on Pb/Zn mine tailings, five plant growth promoting endophytic bacterial strains (PGPE) were selected due to their ability to promote plant growth and to utilize ACC as the sole nitrogen source. The five isolates were identified as Bacillus pumilus E2S2, Bacillus sp. E1S2, Bacillus sp. E4S1, Achromobacter sp. E4L5 and Stenotrophomonas sp. E1L and subsequent testing revealed that they all exhibited traits associated with plant growth promotion, such as production of indole-3-acetic acid and siderophores and solubilization of phosphorus. These five strains showed high resistance to heavy metals (Cd, Zn and Pb) and various antibiotics. Further, inoculation of these ACC utilizing strains significantly increased the concentrations of water extractable Cd and Zn in soil. Moreover, a pot experiment was conducted to elucidate the effects of inoculating metal-resistant ACC utilizing strains on the growth of S. plumbizincicola and its uptake of Cd, Zn and Pb in multi-metal contaminated soils. Out of the five strains, B. pumilus E2S2 significantly increased root (146%) and shoot (17%) length, fresh (37%) and dry biomass (32%) of S. plumbizincicola as well as plant Cd uptake (43%), whereas Bacillus sp. E1S2 significantly enhanced the accumulation of Zn (18%) in plants compared with non-inoculated controls. The inoculated strains also showed high levels of colonization in rhizosphere and plant tissues. Results demonstrate the potential to improve phytoextraction of soils contaminated with multiple heavy metals by inoculating metal hyperaccumulating plants with their own selected functional endophytic bacterial strains.
内生菌辅助植物修复最近被认为是一种成功的金属污染土壤生态修复方法，然而，关于内生细菌对多金属污染土壤中金属超积累植物的植物提取能力的影响，目前所知甚少。我们研究的目的是从新发现的锌/镉超积累植物东南景天的组织中分离和鉴定抗金属和利用1-氨基环丙烷-1-羧酸（ACC）的内生细菌，并研究这些内生细菌菌株是否能提高多金属污染土壤的植物提取效率。在从生长于铅锌矿尾矿上的东南景天组织中分离出的42株抗金属细菌菌株中，选择了5株促进植物生长的内生细菌菌株（PGPE），因为它们具有促进植物生长和利用ACC作为唯一氮源的能力。这5株分离菌被鉴定为短小芽孢杆菌E2S2、芽孢杆菌属E1S2、芽孢杆菌属E4S1、无色杆菌属E4L5和嗜麦芽窄食单胞菌属E1L，随后的测试表明，它们都表现出与促进植物生长相关的特性，如吲哚-3-乙酸和铁载体的产生以及磷的溶解。这5株菌株对重金属（镉、锌和铅）和各种抗生素具有高度抗性。此外，接种这些利用ACC的菌株显著增加了土壤中可提取的镉和锌的浓度。此外，进行了盆栽试验，以阐明接种抗金属利用ACC的菌株对东南景天在多金属污染土壤中的生长及其对镉、锌和铅的吸收的影响。在这5株菌株中，短小芽孢杆菌E2S2显著增加了东南景天的根长（146%）和地上部分长度（17%）、鲜重（37%）和干生物量（32%）以及植物对镉的吸收（43%），而芽孢杆菌属E1S2与未接种对照相比，显著提高了植物中锌的积累（18%）。接种的菌株在根际和植物组织中也表现出高水平的定殖。结果表明，通过用其自身选择的功能性内生细菌菌株接种金属超积累植物，有可能提高对多种重金属污染土壤的植物提取效率。
Zotero 插件