Boosting Plant Growth in Contaminated Soil Using Heavy-Metal-Tolerant Bacteria

Greg Howard
18th June, 2024

Boosting Plant Growth in Contaminated Soil Using Heavy-Metal-Tolerant Bacteria

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from Ewha Womans University studied the effects of a heavy-metal-tolerant bacterium, Leifsonia sp. ZP3, on plant growth in contaminated soils
  • Leifsonia sp. ZP3 significantly improved the germination and growth of millet and mustard in soils with low concentrations of cadmium (Cd) and zinc (Zn)
  • Even in soils with higher concentrations of Cd and Zn, ZP3 inoculation enhanced plant growth, making it a promising candidate for phytoremediation efforts
Heavy-metal contamination in agricultural soils poses severe ecological and environmental challenges, including the entry of toxic metals into the food chain, soil degradation, and suppression of plant growth[2]. Traditional remediation methods often fall short, necessitating innovative solutions. Recent research from Ewha Womans University has explored the potential of plant-growth-promoting bacteria (PGPB) to enhance plant growth in heavy-metal-contaminated soils[1]. The study isolated a strain of heavy-metal-tolerant bacteria, Leifsonia sp. ZP3, from forest soil. This strain exhibited resistance to cadmium (Cd) and zinc (Zn), two metals known for their inhibitory effects on plant growth[3]. The researchers focused on evaluating the effects of ZP3 inoculation on the germination and growth of millet (Panicum miliaceum) and mustard (Brassica juncea) in Cd- and Zn-contaminated soils. Leifsonia sp. ZP3 showed significant plant-growth-promoting activities, such as producing indole-3-acetic acid (a plant hormone), solubilizing phosphate (making it available to plants), and demonstrating catalase activity and antioxidant properties. These traits are crucial for mitigating the stress caused by heavy metals and promoting healthier plant growth[4]. In soils with low concentrations of Cd and Zn, ZP3 inoculation led to remarkable improvements. The germination rates of millet and mustard increased by 8.35- and 31.60-fold, respectively, compared to non-inoculated controls. Additionally, the shoot and root lengths of millet increased by 1.77- and 4.44-fold, respectively. The chlorophyll content and seedling vigor index of millet also saw substantial increases, by 4.40 and 18.78 times, respectively. Mustard plants showed similar benefits, with shoot length increasing 1.89-fold and the seedling vigor index improving by 53.11-fold. Even in soils with higher concentrations of Cd and Zn, ZP3 inoculation proved beneficial. The shoot length and seedling vigor index of mustard increased by 1.98- and 2.07-fold, respectively, compared to the control group. These results indicate that Leifsonia sp. ZP3 can significantly enhance plant growth and development in heavy-metal-contaminated soils, making it a promising candidate for phytoremediation efforts. Phytoremediation involves using plants to remove, transfer, stabilize, or destroy contaminants in soil and water. This method is environmentally friendly and cost-effective but often requires enhancement to be truly effective in heavily contaminated areas[2]. The use of PGPB like Leifsonia sp. ZP3 can significantly expedite the process by promoting plant growth and increasing the uptake of heavy metals by plants. Previous studies have highlighted the potential of PGPB in agriculture, particularly in enhancing plant growth through various mechanisms such as phosphate solubilization, nitrogen fixation, and phytohormone production[4]. This study builds on those findings by demonstrating the specific benefits of a heavy-metal-tolerant PGPB strain in contaminated soils. The research from Ewha Womans University adds a crucial piece to the puzzle of sustainable agriculture and environmental remediation. By isolating and utilizing bacteria like Leifsonia sp. ZP3, we can improve the efficiency of phytoremediation, making it a more viable solution for cleaning up contaminated soils and promoting healthier plant growth. This approach not only addresses the immediate problem of soil contamination but also contributes to the broader goal of sustainable agricultural practices.

EnvironmentBiochemPlant Science

References

Main Study

1) Enhancement of the germination and growth of Panicum miliaceum and Brassica juncea in Cd- and Zn-contaminated soil inoculated with heavy-metal-tolerant Leifsonia sp. ZP3.

Published 17th June, 2024

https://doi.org/10.1007/s11274-024-04053-4

Related Studies

2) Advances in microbe-assisted reclamation of heavy metal contaminated soils over the last decade: A review.

https://doi.org/10.1016/j.jenvman.2017.04.060

3) Resistance of a Halobacterium salinarum isolate from a solar saltern to cadmium, lead, nickel, zinc, and copper.

https://doi.org/10.1007/s10482-020-01475-6

4) Plant growth-promoting rhizobacteria (PGPR): emergence in agriculture.

https://doi.org/10.1007/s11274-011-0979-9


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