Selenium and Bacillus proteolyticus SES synergistically enhanced ryegrass to remediate Cu-Cd-Cr contaminated soil

Min Nie; Chihhung Wu; Yanni Tang; Guangyu Shi; Xu Wang; Chengxiao Hu; Jun Cao; Xiaohu Zhao

doi:10.1016/j.envpol.2023.121272

Selenium and Bacillus proteolyticus SES synergistically enhanced ryegrass to remediate Cu-Cd-Cr contaminated soil

Environ Pollut. 2023 Apr 15:323:121272. doi: 10.1016/j.envpol.2023.121272. Epub 2023 Feb 11.

Authors

Min Nie¹, Chihhung Wu², Yanni Tang³, Guangyu Shi⁴, Xu Wang⁵, Chengxiao Hu³, Jun Cao³, Xiaohu Zhao⁶

Affiliations

¹ College of Resources and Environment, Huazhong Agricultural University / Research Center of Trace Elements, Wuhan, 430070, China; Fujian Provincial Key Laboratory of Resources and Environment Monitoring & Sustainable Management and Utilization, Sanming University, Sanming, 365004, China.
² Fujian Provincial Key Laboratory of Resources and Environment Monitoring & Sustainable Management and Utilization, Sanming University, Sanming, 365004, China.
³ College of Resources and Environment, Huazhong Agricultural University / Research Center of Trace Elements, Wuhan, 430070, China.
⁴ College of Environment Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
⁵ Institute of Quality Standard and Monitoring Technology for Agro-products of Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
⁶ College of Resources and Environment, Huazhong Agricultural University / Research Center of Trace Elements, Wuhan, 430070, China. Electronic address: xhzhao@mail.hzau.edu.cn.

PMID: 36780973
DOI: 10.1016/j.envpol.2023.121272

Abstract

Heavy metal compound contaminated soil is an ecological threat, and soil containing copper (Cu), cadmium (Cd) and chromium (Cr) simultaneously is widely distributed. The application of phytoremediation in heavy metal combined contamination is still limited. In this study, to explore whether and how exogenous selenium (Se) and Bacillus proteolyticus SES enhance the remediation of combined Cu-Cd-Cr contaminated soil by ryegrass, pot experiments were carried out. Se alone or in combination with B. proteolyticus SES treatment increased the removal rates of heavy metals in the rhizosphere soil by 17.38%-157.25% relative to the control, while Se + B. proteolyticus SES treatment played a greater role in improving the heavy metals tolerance of ryegrass and increasing the activity of soil acid phosphatase. Moreover, Se and B. proteolyticus SES favored the preferential recruitment of specific taxa with the capacity of plant growth promotion and heavy metals resistance to the rhizosphere. The rhizosphere soil of Se treatment was specifically enriched with Lysobacter, Rhodanobacter, Micrococcales, Paenarthrobacter, and Adhaeribacter, while from class Bacilli to genus Bacillus enriched extensively and specifically in the rhizosphere of B. proteolyticus SES + Se treatment. Furthermore, five functional beneficial rhizosphere microbes including: Microbacterium sp., Pseudomonas extremaustralis, Bacillus amyloliquefaciens, Priestia megaterium, and Bacillus subtilis were isolated from the two treatments with the best remediation effect and synthetic communities (SynComs) were constructed. SynComs inoculation experiment further demonstrated the role of specific beneficial microbes in regulating the bioavailability of heavy metals. Results revealed that Se supplementation efficiently facilitated the phytoextraction of combined Cu-Cd-Cr contaminated soil, and B. proteolyticus SES inoculation showed the synergistical enhancement effect in the presence of Se.

Keywords: Heavy metal compound contamination; Phytoremediation; Rhizosphere microbiome; Rhizosphere soil; Selenium.

MeSH terms

Bacillus*
Biodegradation, Environmental
Cadmium / analysis
Chromium
Lolium*
Metals, Heavy* / analysis
Rhizosphere
Selenium*
Soil
Soil Pollutants* / analysis

Substances

Cadmium
Selenium
Chromium
Soil
Metals, Heavy
Soil Pollutants

Supplementary concepts

Bacillus proteolyticus