Streptomycin application has no detectable effect on bacterial community structure in apple orchard soil

Area of Science:

• Agricultural Microbiology
• Environmental Science
• Bacterial Ecology

Background:

• Streptomycin is widely used to manage fire blight disease in apple orchards.
• Concerns exist regarding the nontarget environmental effects of streptomycin application.
• Limited data is available on streptomycin's impact on soil microbial communities in agricultural settings.

Purpose of the Study:

• To investigate the effects of aerial streptomycin application on nontarget soil bacterial communities in a commercial apple orchard.
• To assess immediate impacts on bacterial community structure, diversity, and evenness.

Main Methods:

• Soil samples were collected from treated and untreated apple trees over two consecutive years.
• Bacterial DNA was profiled using 16S rRNA gene tag-pyrosequencing from cultured and uncultured sources.
• Multivariate statistical analyses were employed to compare community structures.

Main Results:

• No significant differences were observed in bacterial community structure between streptomycin-treated and untreated soil.
• Shannon diversity and Pielou's evenness tests indicated no discernible response to streptomycin application.
• Cultured and uncultured bacterial communities showed resilience to streptomycin treatment.

Conclusions:

• Aerial streptomycin application for fire blight management has minimal immediate effects on apple orchard soil bacterial communities.
• The study suggests that antibiotic use in this agroecosystem poses limited risks to nontarget soil bacteria.
• Findings contribute to understanding the environmental profile of antibiotic use in agriculture.