4. Conclusion

In this study, we designed qPCR standards for quantifying various taxonomic and functional genes used in microbial ecology, such as those involved in C and N cycling, by synthesizing double-stranded DNA sequences as gBlocks gene fragments. We show that synthetic DNA standards performed equally well as traditional plasmid standards in producing linear qPCR calibration curves, yielding precise and efficient results for a broad range of soils. The application of synthetic DNA standards for qPCR assays is however not limited to soils, but can be recommended for all kind of genes from a large variety of environments, such as water, air and sediments, whenever qPCR is needed for gene quantification.