Phenanthrene-degrading bacteria on root surfaces: a natural defense that protects plants from phenanthrene contamination
Phenanthrene-degrading bacteria on root surfaces: a natural defense that protects plants from phenanthrene contamination
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根表面的菲降解细菌：保护植物免受菲污染的自然防御
DOI：
10.1007/s11104-018-3575-z
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发表时间：
2018-04-01
期刊：
影响因子：
4.9
通讯作者：
Zhao, Zhenhua
中科院分区：
文献类型：
--
作者：
Liu, Juan;Zhang, Zhiming;Zhao, Zhenhua
目的 根表细菌（BRS）由于其多种生态功能以及降解顽固有机污染物的能力，在农业中具有极其重要的实际意义。然而，关于多环芳烃（PAH）降解根表细菌对植物吸收和积累多环芳烃的影响知之甚少。因此，我们试图研究多环芳烃降解根表细菌是否能保护植物免受多环芳烃污染。
方法 利用富集培养法从多环芳烃污染场地生长的植物根表分离出一株菲降解细菌。用分离出的细菌进行芽浸泡或根部接种后，进行温室盆栽实验。采用高效液相色谱法（HPLC）分析土壤和植物样本中的菲残留量。
结果 从小飞蓬（Conyza canadensis L. Cronq.）根表分离出一株菲降解细菌鞘氨醇单胞菌属RS2（Sphingobium sp. RS2），它能在72小时内降解超过99%的菲（100 mg/L）。用RS2 - gfp菌株（绿色荧光蛋白标记的RS2）接种紫花苜蓿（Medicago sativa L.）植株表明，被RS2 - gfp菌株定殖的紫花苜蓿植株在根部和地上部分积累菲的能力均较低。与未接种RS2 - gfp的处理相比，通过芽浸泡接种RS2 - gfp的植株根部和地上部分菲的浓度分别降低了39.9%和62.5%，通过根部接种分别降低了25.1%和35.8%。
结论 我们提出多环芳烃降解根表细菌能够保护植物免受多环芳烃污染。这项工作的结果应该有利于多环芳烃污染场地的食品安全和人类健康。
Aims Bacteria on root surfaces (BRS) have tremendous practical importance in agriculture because of their various ecological functions and ability to degrade recalcitrant organic pollutants. However, little is known on the influence of polycyclic aromatic hydrocarbon (PAH)-degrading BRS on the uptake and accumulation of PAHs by plants. Thus, we sought to investigate whether the PAH-degrading BRS would protect plants from PAH contamination.Methods A phenanthrene-degrading bacterium was isolated from the root surface of a plant growing in a PAH-contaminated site using enrichment culture. After bud soaking or root inoculation with the isolated bacterium, greenhouse container experiments were performed. Phenanthrene residues in soil and plant samples were analyzed by high-performance liquid chromatography (HPLC).Results A phenanthrene-degrading bacterium, Sphingobium sp. RS2, was isolated from the root surface of Conyza canadensis L. Cronq. and could degrade more than 99% of phenanthrene (100 mg.L-1) within 72 h. Inoculating alfalfa (Medicago sativa L.) plants with strain RS2-gfp (gfp-labeled RS2) revealed that alfalfa plants colonized with strain RS2-gfp exhibited a lower capacity for phenanthrene accumulation in both roots and shoots. Compared with the RS2-gfp-free treatment, the concentration of phenanthrene in RS2-gfp-inoculated plants was reduced by 39.9% and 62.5% in roots and shoots via bud soaking and by 25.1% and 35.8% via root inoculation, respectively.Conclusions We propose that PAH-degrading BRS can protect plants from PAH contamination. The results of this work should benefit food safety and human health in PAH-contaminated sites.