AIT Austrian Institute of Technology GmbH, Bioresources Unit, Seibersdorf, Austria.
J Appl Microbiol. 2010 Apr;108(4):1471-84. doi: 10.1111/j.1365-2672.2010.04670.x. Epub 2010 Jan 11.
To characterize bacteria associated with Zn/Cd-accumulating Salix caprea regarding their potential to support heavy metal phytoextraction.
Three different media allowed the isolation of 44 rhizosphere strains and 44 endophytes, resistant to Zn/Cd and mostly affiliated with Proteobacteria, Actinobacteria and Bacteroidetes/Chlorobi. 1-Aminocyclopropane-1-carboxylic acid deaminase (ACCD), indole acetic acid and siderophore production were detected in 41, 23 and 50% of the rhizosphere isolates and in 9, 55 and 2% of the endophytes, respectively. Fifteen rhizosphere bacteria and five endophytes were further tested for the production of metal-mobilizing metabolites by extracting contaminated soil with filtrates from liquid cultures. Four Actinobacteria mobilized Zn and/or Cd. The other strains immobilized Cd or both metals. An ACCD- and siderophore-producing, Zn/Cd-immobilizing rhizosphere isolate (Burkholderia sp.) and a Zn/Cd-mobilizing Actinobacterium endophyte were inoculated onto S. caprea. The rhizosphere isolate reduced metal uptake in roots, whereas the endophyte enhanced metal accumulation in leaves. Plant growth was not promoted.
Metal mobilization experiments predicted bacterial effects on S. caprea more reliably than standard tests for plant growth-promoting activities.
Bacteria, particularly Actinobacteria, associated with heavy metal-accumulating Salix have the potential to increase metal uptake, which can be predicted by mobilization experiments and may be applicable in phytoremediation.
研究与 Zn/Cd 积累柳属植物（Salix caprea）相关的细菌，以确定它们在支持重金属植物提取方面的潜力。
三种不同的培养基允许分离出 44 株根际菌株和 44 株内生菌，这些菌株对 Zn/Cd 具有抗性，主要与变形菌门、放线菌门和拟杆菌门/绿菌门有关。在 41%、23%和 50%的根际分离物中检测到 1-氨基环丙烷-1-羧酸脱氨酶（ACCD）、吲哚乙酸和铁载体的产生，而在 9%、55%和 2%的内生菌中分别检测到 1-氨基环丙烷-1-羧酸脱氨酶（ACCD）、吲哚乙酸和铁载体的产生。进一步对 15 株根际细菌和 5 株内生菌进行了金属代谢产物的产生测试，通过用液体培养物的滤液提取受污染的土壤。四种放线菌可移动 Zn 和/或 Cd。其他菌株则固定 Cd 或两种金属。一个产生 ACCD 和铁载体、固定 Zn/Cd 的根际分离物（伯克霍尔德菌属）和一个 Zn/Cd 可移动的放线菌内生菌被接种到柳属植物上。根际分离物减少了根部对金属的吸收，而内生菌则增强了叶片对金属的积累。植物生长没有得到促进。
与标准的植物促生活性测试相比，金属动员实验更能预测细菌对柳属植物的影响。
与重金属积累的柳树相关的细菌，特别是放线菌，具有增加金属吸收的潜力，这可以通过动员实验来预测，并且可能适用于植物修复。
