Experimental evidence for the impact of soil viruses on carbon cycling during surface plant litter decomposition

Michaeline B N Albright,Migun Shakya,Joanne B Emerson,John Dunbar,La Verne Gallegos-Graves,Kelli L Feeser,Kyana Montoya

doi:10.1038/s43705-022-00109-4

Abstract

To date, the potential impact of viral communities on biogeochemical cycles in soil has largely been inferred from correlational evidence, such as virus-driven changes in microbial abundances, viral auxiliary metabolic genes, and links with soil physiochemical properties. To more directly test the impact of soil viruses on carbon cycling during plant litter decomposition, we added concentrated viral community suspensions to complex litter decomposer communities in 40-day microcosm experiments. Microbial communities from two New Mexico alpine soils, Pajarito (PJ) and Santa Fe (SF), were inoculated onto grass litter on sand, and three treatments were applied in triplicate to each set of microcosms: addition of buffer (no added virus), live virus (+virus), or killed-virus (+killed-virus) fractions extracted from the same soil. Significant differences in respiration were observed between the +virus and +killed-virus treatments in the PJ, but not the SF microcosms. Bacterial and fungal community composition differed significantly by treatment in both PJ and SF microcosms. Combining data across both soils, viral addition altered links between bacterial and fungal diversity, dissolved organic carbon and total nitrogen. Overall, we demonstrate that increasing viral pressure in complex microbial communities can impact terrestrial biogeochemical cycling but is context-dependent.

Highlights

Viruses that infect microbial hosts have a major impact on their immediate host and can influence larger scale environmental processes
Soil collection, whole microbial community inoculum, and virus extraction Soils were collected from two locations, Pajarito Mountain Los Alamos (PJ) (35.894208°N, 106.391817°W) and Mount Baldy Santa Fe (SF) (35.793527°N, 105.800391°W) in northern New Mexico during the first week of November in 2020
We used dissolved organic carbon (DOC) and total nitrogen (TN) measurements from the final microcosm sampling which corresponds to the sampling time for the microbial community data

Summary

INTRODUCTION

Viruses that infect microbial hosts have a major impact on their immediate host and can influence larger scale environmental processes. Recent research suggests that viralmediated processes impact terrestrial C and nutrient cycling [11–14]. Differences between marine and terrestrial ecosystems that may influence the impact of viral-mediated C cycling include differences in microbe and virus turnover times and the environmental spatial structure and heterogeneity [14, 15]. The impact of the soil virome on biogeochemical cycling has largely been inferred from viral driven changes in microbial populations (e.g., predator-prey cycles) Changes in the composition of microbial communities are increasingly recognized as a factor that can drive substantial variation in soil carbon cycling [30–35]. Received: January 2022 Revised: February 2022 Accepted: 16 February 2022 quantity of virus would alter microbially driven C cycling during Initial soil total microbial community and viral DNA extraction plant litter decomposition by changing microbial community for metagenomic sequencing dynamics.

METHODS

RESULTS AND DISCUSSION

CONCLUSIONS