Abstract:

Aims: To systematically examine soil viral community composition and assess their carbon metabolic functional potential across urban wetland ecosystems. 

Methods: Taking the five types of sample plots, including trees, shrubs and grasslands, shrub grassland, reed marsh, shoals and ponds distributed widely in Xixi National Wetland in Hangzhou, Zhejiang Province as the research objects. This study investigates soil viral diversity patterns and carbon metabolic gene composition across these five habitats using virus metagenomic sequencing coupled with bioinformatics analysis. 

Results：There were significant differences in virus richness and diversity among the five habitat types (P<0.05), with hierarchical rankings as follows: shrub grassland> trees, shrubs and grasslands> reed marsh >shoals>ponds; The structural equation modeling analysis showed that this spatial pattern was predominantly mainly driven by soil physico-chemical properties, with the order of effect value was pH>soil moisture>SOC≈TN>soil temperature. The contribution of comprehensive effect value of virus host and virus diversity was in the order of TN>SOC>soil temperature, and the direct effect of virus host on virus diversity was the strongest (effect value=0.87); A total of 158 unique carbohydrate transport and metabolism (G) genes were identified, including 13 distinct carbohydrate active enzyme (CAZyme) families. Among these glycosyltransferases accounted for the highest proportion (65.8%), indicating that soil viruses may play an important role in wetland carbon cycling through glycosylation-mediated processes. 

Conclusion: The diversity of soil viruses in Xixi Wetland exhibits significant spatial heterogeneity. This distribution pattern is closely linked to variations in soil physical and chemical properties (especially the key factors such as SOC, TN and soil water content). A total of 158 distinct functional genes associated with carbohydrate transport and metabolism (G) were identified across sampled regions, including approximately 13 CAZyme genes. These genes contribute to wetland carbon cycling processes through regulating the metabolic pathways of host microorganisms.

Key words: wetlands, virus metagenomic sequencing, soil organic carbon sequestration, CAZymes genes, ecological function