Overview - EN ISO 17601:2025 (Soil quality, qPCR)
EN ISO 17601:2025 (CEN adoption of ISO 17601) defines a standardized quantitative PCR (qPCR) workflow to estimate the abundance of selected microbial gene sequences from DNA directly extracted from soil. The method provides an estimate of selected microbial groups (taxonomic or functional markers) and supports routine, comparable measurements of soil quality and microbial community indicators. This edition replaces the earlier ISO 17601:2016 and is intended for laboratories performing molecular soil analyses.
Key topics and technical requirements
- Principle: qPCR quantification of target gene sequences from soil-extracted DNA to estimate abundance of microbial groups. The standard notes gene copy number is not always equivalent to organism counts (e.g., variable rRNA operon copy numbers; DNA from dead cells may be amplified).
- Test materials: requirements for DNA extracts, bacterial isolates, plasmid standards, enzymes, reagents, buffers and culture media used to prepare standards and controls.
- Apparatus: standard qPCR instrumentation and supporting laboratory equipment.
- Procedure: structured into main tasks:
- qPCR standard preparation and calibration (amplicon design, standard curve generation, calibration)
- Soil DNA template preparation and inhibition testing (extraction, purification, inhibition checks, dilution strategies)
- qPCR assay execution (assay setup, controls)
- Validation and analysis (assay performance, copy number calculation, critical-step examination)
- Quality control and validation: calibration of standards, inhibition testing, repeatability and reproducibility assessment (international ring test referenced in Annex B).
- Annexes: informative guidance such as TaqMan qPCR steps, ring-test design, and examples of established primer systems for soil marker genes (Annex C).
Applications and who uses it
- Environmental and soil testing laboratories implementing molecular soil quality indicators
- Researchers in soil microbiology, agronomy, ecology and biogeochemistry studying microbial community abundance and functional genes
- Agricultural consultants and land managers monitoring soil health and treatment effects
- Remediation and environmental monitoring programs requiring standardized, comparable qPCR-based microbial data
- Regulatory bodies and standardization committees evaluating molecular methods for soil quality assessment
Related standards and context
- EN ISO 17601 complements soil nucleic-acid extraction standards (e.g., ISO 11063) and other microbial ecology standards. It is intended for use alongside laboratory quality management practices and method validation guidance to ensure reliable, comparable soil qPCR results.
Keywords: EN ISO 17601:2025, soil quality, qPCR, soil DNA, microbial gene abundance, quantitative PCR, soil microbial communities, ISO standard, CEN.
