Pang Jie, Liu Yue-Min, Huang Yong-Chun, Wang Chang-Rong, Liu Bin, Liu Zhong-Qi, Huang Yi-Zong, Huang Yan-Fei, Zhang Chang-Bo
School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China.
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China.
Huan Jing Ke Xue. 2021 Sep 8;42(9):4471-4480. doi: 10.13227/j.hjkx.202101192.
The combination of endophytes and hyperaccumulator plants can significantly improve the efficiency of heavy metal phytoremediation in contaminated soil. A plant endophyte named R-13 was isolated from rice roots in a cadmium (Cd) contaminated paddy field. This strain exhibited a strong tolerance to Cd and could grow on a solid medium with a Cd concentration of 300 mg·kg. The R-13 strain was able to produce siderophores and Indole acetic acid (IAA), through color reactions. In addition, Pikovskaya's and Ashby's solid medium tests showed that the R-13 strain had a lower capacity for dissolving phosphorus but a higher capacity for fixing nitrogen. In the pot experiment, high-throughput sequencing technology was used to track the colonization of the R-13 strain in L. roots. Three days after inoculation, the relative abundance of in the root of L. had increased by 201.88% compared to the blank control (CK) and after two inoculations, the relative abundance of in the root of L. had increased by 1182.44% compared to CK. The relative abundance of in the root of L. began to decrease significantly from 5 days after inoculation. Inoculation with 20 mL·pot of R-13 fermentation broth resulted in no significant effects on the Cd content of roots, stems, leaves, or fruits of L. With 40 mL·pot of fermentation broth, the Cd content of vegetative organs and fruits was significantly increased. When it reached 200 mL·pot, the Cd content of vegetative organs was the highest, with Cd concentrations in the roots, stems, leaves, and fruits increasing by 84.42%, 43.67%, 64.06%, and 20.29%, respectively. In conclusion, root inoculation with endophytic R-13 can significantly increase the relative content of in the root system and enhance Cd absorption of L. Therefore, this strain has excellent prospects for application in the phytoremediation of soil contaminated with Cd.
内生菌与超富集植物相结合可显著提高污染土壤中重金属植物修复的效率。从镉（Cd）污染稻田的水稻根系中分离出一种名为R-13的植物内生菌。该菌株对Cd表现出较强的耐受性，能够在Cd浓度为300 mg·kg的固体培养基上生长。通过颜色反应表明，R-13菌株能够产生铁载体和吲哚乙酸（IAA）。此外，Pikovskaya培养基和Ashby培养基固体试验表明，R-13菌株溶解磷的能力较低，但固氮能力较高。在盆栽试验中，利用高通量测序技术追踪R-13菌株在龙葵根系中的定殖情况。接种3天后，龙葵根系中该菌的相对丰度比空白对照（CK）增加了201.88%，两次接种后，龙葵根系中该菌的相对丰度比CK增加了11,824.4%。接种后5天起，龙葵根系中该菌的相对丰度开始显著下降。每盆接种20 mL R-13发酵液对龙葵根、茎、叶和果实的Cd含量无显著影响。每盆接种40 mL发酵液时，营养器官和果实的Cd含量显著增加。当达到每盆200 mL时，营养器官的Cd含量最高，根、茎、叶和果实中的Cd浓度分别增加了84.42%、43.67%、64.06%和20.29%。总之，内生菌R-13接种到根系中可显著提高龙葵根系中该菌的相对含量，并增强龙葵对Cd的吸收。因此，该菌株在Cd污染土壤的植物修复中具有良好的应用前景。
