Fluorescent pseudomonads occurring in Macrotermes subhyalinus mound structures decrease Cd toxicity and improve its...

Area of Science:

• Environmental Microbiology
• Soil Science
• Bioremediation

Background:

• Termite mound soil harbors diverse microbial communities.
• Metal-tolerant bacteria, particularly fluorescent pseudomonads, are found in these unique environments.
• Cadmium contamination poses a significant threat to soil health and plant growth.

Purpose of the Study:

• To isolate and identify cadmium-tolerant fluorescent pseudomonads from termite mound soil.
• To evaluate the efficacy of these bacterial isolates in enhancing sorghum plant growth and cadmium uptake.
• To investigate the impact of bacterial inoculation on arbuscular mycorrhizal colonization in cadmium-contaminated soil.

Main Methods:

• Isolation and characterization of fluorescent pseudomonad strains from Macrotermes subhyalinus termite mound soil.
• Greenhouse experiments inoculating Sorghum bicolor with isolated bacteria in cadmium-spiked soil.
• Assessment of plant biomass, root and shoot growth, and cadmium uptake.
• Measurement of arbuscular mycorrhizal (AM) colonization.
• Analysis of microbial functional diversity using in situ catabolic potential assays.

Main Results:

• Isolated bacterial strains, primarily Pseudomonas monteillii, exhibited tolerance to cadmium.
• Inoculation with fluorescent pseudomonads significantly improved shoot and total biomass of sorghum plants.
• Bacterial inoculation enhanced cadmium uptake by sorghum plants.
• Fluorescent pseudomonads significantly increased arbuscular mycorrhizal colonization in cadmium-contaminated soil.
• Microbial communities in inoculated soils showed altered metabolic potentials, favoring utilization of specific organic acids.

Conclusions:

• Termite mound soil is a rich source of metal-tolerant fluorescent pseudomonads with bioremediation potential.
• Fluorescent pseudomonads can enhance plant growth and metal phytoextraction in contaminated soils.
• These bacteria play a role in improving soil microbial community structure and function.
• This study highlights the potential of using termite mound-derived bacteria for the bioremediation of metal-contaminated sites.