Bacteriophage-host depth distribution patterns in soil are maintained after nutrient stimulation in vitro.

Area of Science:

• Environmental microbiology
• Virology
• Soil ecology

Background:

• Viruses are ecologically vital, but bacteriophage-host dynamics in soil depth profiles remain understudied.
• Environmental factors like nutrients and stress influence viral reproduction (lytic/lysogenic) and ecological impact.
• Soil depth profiles offer unique insights into virus-host relationships influenced by geochemistry.

Purpose of the Study:

• To investigate bacteriophage-host interactions in soil depth profiles under nutrient stimulation.
• To determine how geochemical properties and nutrient availability affect viral and bacterial communities.
• To assess the conservation of virus-host interaction patterns in response to environmental changes.

Main Methods:

• Batch enrichment experiments using soil from varying depths (0-140 cm) as inoculum.
• Nutrient stimulation to observe viral and bacterial responses.
• Analysis of viral and bacterial abundance, diversity, community structure, and lysogenic fraction.

Main Results:

• Both viral and bacterial abundance increased with nutrient addition.
• Viral abundance decreased with soil depth, leading to a lower virus-to-bacteria ratio.
• Bacterial diversity decreased with depth and was influenced by soil type, viral abundance, and virus-to-bacteria ratio.
• Lysogeny increased with soil depth, mirroring original soil conditions.
• Bacterial communities were dominated by Bacilli, Proteobacteria, and Clostridia post-stimulation.
• Viral and bacterial community structures varied with soil horizons.
• Virus-host interaction patterns under nutrient stimulation reflected pre-existing geochemical influences.

Conclusions:

• Nutrient stimulation alone did not significantly alter viral reproductive strategies in terrestrial ecosystems.
• Existing virus-host interaction patterns, shaped by long-term environmental adaptation, were largely conserved.
• Factors beyond short-term trophic changes, such as stress and host adaptation, may be crucial for community-level shifts in virus-host dynamics.