Viral lysing can alleviate microbial nutrient limitations and accumulate recalcitrant dissolved organic matter components in soil

• Published in: The ISME Journal 2023-08, Vol.17 (8), p.1247-1256
• Main Authors: Tong, Di, Wang, Youjing, Yu, Haodan, Shen, Haojie, Dahlgren, Randy A., Xu, Jianming
• Format: Article
• Language: English
• Subjects: 631/158/855; 631/45/47; 704/47; Biogeochemistry; Biomedical and Life Sciences; Carbon; Carbon Cycle; Carbon dioxide; Carbon dioxide emissions; Carbon Sequestration; Carbon sinks; Carbon sources; Dissolved Organic Matter; Ecology; Enzymatic activity; Enzyme activity; Evolutionary Biology; Life Sciences; Microbial activity; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microorganisms; Nutrient cycles; Nutrient dynamics; Organic soils; Phages; Soil - chemistry; Soils
• ISSN: 1751-7362; 1751-7370; 1751-7370
• DOI: 10.1038/s41396-023-01438-5

Viruses are critical for regulating microbial communities and biogeochemical processes affecting carbon/nutrient cycling. However, the role of soil phages in controlling microbial physiological traits and intrinsic dissolved organic matter (DOM) properties remains largely unknown. Herein, microcosm experiments with different soil phage concentrates (including no-added phages, inactive phages, and three dilutions of active phages) at two temperatures (15 °C and 25 °C) were conducted to disclose the nutrient and DOM dynamics associated with viral lysing. Results demonstrated three different phases of viral impacts on CO 2 emission at both temperatures, and phages played a role in maintaining Q 10 within bounds. At both temperatures, microbial nutrient limitations (especially P limitation) were alleviated by viral lysing as determined by extracellular enzyme activity (decreased V angle with active phages). Additionally, the re-utilization of lysate-derived DOM by surviving microbes stimulated an increase of microbial metabolic efficiency and recalcitrant DOM components (e.g., SUV254, SUV260 and HIX). This research provides direct experimental evidence that the “viral shuttle” exists in soils, whereby soil phages increase recalcitrant DOM components. Our findings advance the understanding of viral controls on soil biogeochemical processes, and provide a new perspective for assessing whether soil phages provide a net “carbon sink” vs. “carbon source” in soils.