9% of the total variation of microbial community structure, 9.6%

of detected functional genes involved in C cycling, and 9.4% of detected functional genes in N cycling in this study. After accounting for the effects of the CO2 treatment, the selected variables from plant and soil could significantly explain more than 42% of the total variances of microbial community structure. Our previous studies have demonstrated that increased C inputs at eCO2 stimulate microbial activity and regulate their composition [13, 25]. Consistently, our statistical analysis suggests that the biomass of N2-fixing legume species (BLP) and the number of plant functional groups selleck screening library (PFG) have significantly positive correlations with the atmospheric CO2 level. These strong correlations could arise because increased plant-derived substrates at eCO2 could fuel heterotrophic metabolism in soil [44]. Such a strong correlation with the biomass of N2-fixing legume species (BLP) may result in an increased amount of N derived from the JQEZ5 in vitro atmosphere. Therefore, significant increases in plant biomass were associated

with the significant increase in the abundance of nifH genes, but little effect was seen in soil N dynamics. Soil microbial community structure may be shaped by soil properties, such as pH and moisture [45]. For example, soil pH and moisture changed at eCO2 in the BioCON study [6, 46], and a significant correlation between the soil microbial community compositions and soil pH was observed with a survey of 88 soils

across North and South America [47]. In this study, soil N% at the depth of 0-10 cm (SN0-10) and 10–20 cm (SN10-20), soil C and N ratio at the Selleck Tozasertib depth of 10–20 cm (SCNR10-20), and soil pH (pH) were identified as the most important soil factors shaping microbial community structures. In addition, significant correlations were also observed between the plant and soil factors, such as positive correlations between pH and BBG, pH and PFG, SCNR10-20 and BBG, and negative correlations between SCNR10-20 and BLP. These results suggested that, in addition to direct effects of atmospheric CO2 on soil microbial C and N cycling, such as CO2 fixation, eCO2-induced indirect effects on plant and soil properties significantly Florfenicol impact the soil microbial community structure and modify their ecosystem functioning. The simultaneous enhances in the processes involved in CO2 fixation, C degradation, N fixations and partial denitrification could be the reason that no significant difference was detected in total soil C and N. Conclusions GeoChip was successfully used to illuminate the response of soil microbial communities to eCO2. The results showed that microbial C and N cycling were altered dramatically at eCO2, and the eCO2-induced effects, such as increased plant biomass and altered soil pH, may largely shape the soil microbial community structure and regulate their ecosystem functioning.