Two microbes assisting Miscanthus floridulus in remediating multi-metal(loid)s-contaminated soil

Area of Science:

• Environmental Science
• Microbiology
• Bioremediation

Background:

• Soil contamination by multi-metal(loid)s poses significant environmental risks.
• Miscanthus species are known for their tolerance to metal(loid)s and potential in phytoremediation.
• Plant growth-promoting bacteria (PGPB) can enhance plant growth and metal uptake.

Purpose of the Study:

• To investigate the synergistic effects of Miscanthus floridulus and two PGPB (TS8 and MR2) on the phytoextraction of multi-metal(loid)s-contaminated soil.
• To assess the impact of PGPB inoculation on Miscanthus growth and physiological parameters.
• To analyze the changes in soil properties and rhizosphere microbial community structure.

Main Methods:

• Phytoextraction experiments using Miscanthus floridulus inoculated with PGPB TS8 and MR2.
• Analysis of metal(loid) concentrations in soil.
• Measurement of plant biomass, height, and physiological indicators (antioxidant enzymes, chlorophyll).
• Soil pH and nutrient analysis (available P, K).
• High-throughput sequencing for rhizosphere bacterial community analysis.
• Phylogenetic molecular ecological network construction.

Main Results:

• Bacterial inoculation significantly reduced soil concentrations of arsenic, cadmium, lead, and zinc.
• Inoculated Miscanthus exhibited increased biomass and height, indicating enhanced plant growth.
• Elevated activities of antioxidant enzymes in underground tissues and soil, alongside increased available P and K.
• PGPB inoculation altered the rhizosphere bacterial community, reducing diversity but increasing the relative abundance of some PGPB.
• Spearman's test identified Enterobacteriaceae and soil nutrients as critical factors for remediation and growth.

Conclusions:

• The combination of Miscanthus floridulus and PGPB (TS8, MR2) offers a synergistic approach for effective multi-metal(loid) soil remediation.
• PGPB enhance both plant growth and the phytoextraction efficiency of Miscanthus.
• Understanding rhizosphere microbial dynamics is crucial for optimizing phytoremediation strategies.
• This study provides a foundation for regulating Miscanthus remediation efficiency using specific PGPB.