Southern Appalachian Soils and Associated Bacterial Siderophores

Additional Authors

Kemper Reed Rasnake M.S. Microbiology, Department of Biomedical Health Sciences, College of Public Health, ETSU, Johnson City, TN, and Dr. Arpita Nandi, Department of Geosciences, College of Arts and Sciences, ETSU, Johnson City, TN

Abstract

Iron, a macronutrient, is needed by all living organisms for various metabolic activities and to maintain soil quality for healthy vegetation and foster microbiomes. Soluble iron [Fe(II)] can become low in the soil environment that activates bacteria to produce siderophores, a low molecular weight organic substance with high affinity for insoluble iron [Fe(III)]. Bacterial siderophores facilitate iron reduction to Fe(II), making the iron molecules soluble to absorb and utilize by plants and other soil organisms. Siderophore production can vary with soil physicochemical properties. The objective of this study is to examine the physicochemical properties of soil in the southern Appalachian environment and their potential effects on siderophore-producing bacterial populations. Thirteen soil samples were collected from four natural landscapes—upper and lower hillslopes, wetlands, and stream bank—at depths of 3", 6", and 9", plus a control. Soil was tested for texture, moisture, pH, and macronutrients. Results showed wetland soils had the highest clay content (33.3%) and moisture (44.6%), while ridges had higher sand (72.5%) and lower pH (5.3-5.6). Siderophore activity was assessed using Universal Chrome Azurol S (CAS) media, detecting activity irrespective of chemical type. The upper and lower ridges showed low iron (<120 ppm) and low pH (5 - 6.8) which favored siderophore activity. While the iron content was higher in the Wetlands (~150 ppm) and Streambank (~1150 ppm), the alkaline (7.5 - 8) conditions of the soil made the iron insoluble which also promoted siderophore production. Therefore the bacterial siderophore production showed no significant difference between soil types. This study highlights the link between soil biogeochemistry and siderophore production. The findings could aid in isolating bacterial siderophores from specific soil ecosystems for agricultural and medicinal use, drug delivery and treating iron related complications, such as hemochromatosis.

Start Time

16-4-2025 1:30 PM

End Time

16-4-2025 4:00 PM

Presentation Type

Poster

Presentation Category

Science, Technology and Engineering

Student Type

Undergraduate Student

Faculty Mentor

Ranjan Chakraborty

Faculty Department

Biomedical Health Sciences

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Apr 16th, 1:30 PM Apr 16th, 4:00 PM

Southern Appalachian Soils and Associated Bacterial Siderophores

Iron, a macronutrient, is needed by all living organisms for various metabolic activities and to maintain soil quality for healthy vegetation and foster microbiomes. Soluble iron [Fe(II)] can become low in the soil environment that activates bacteria to produce siderophores, a low molecular weight organic substance with high affinity for insoluble iron [Fe(III)]. Bacterial siderophores facilitate iron reduction to Fe(II), making the iron molecules soluble to absorb and utilize by plants and other soil organisms. Siderophore production can vary with soil physicochemical properties. The objective of this study is to examine the physicochemical properties of soil in the southern Appalachian environment and their potential effects on siderophore-producing bacterial populations. Thirteen soil samples were collected from four natural landscapes—upper and lower hillslopes, wetlands, and stream bank—at depths of 3", 6", and 9", plus a control. Soil was tested for texture, moisture, pH, and macronutrients. Results showed wetland soils had the highest clay content (33.3%) and moisture (44.6%), while ridges had higher sand (72.5%) and lower pH (5.3-5.6). Siderophore activity was assessed using Universal Chrome Azurol S (CAS) media, detecting activity irrespective of chemical type. The upper and lower ridges showed low iron (<120 >ppm) and low pH (5 - 6.8) which favored siderophore activity. While the iron content was higher in the Wetlands (~150 ppm) and Streambank (~1150 ppm), the alkaline (7.5 - 8) conditions of the soil made the iron insoluble which also promoted siderophore production. Therefore the bacterial siderophore production showed no significant difference between soil types. This study highlights the link between soil biogeochemistry and siderophore production. The findings could aid in isolating bacterial siderophores from specific soil ecosystems for agricultural and medicinal use, drug delivery and treating iron related complications, such as hemochromatosis.