Overview - ISO/TR 17622:2015 (SSR analysis of sunflower)
ISO/TR 17622:2015 provides a standardized technical report for molecular biomarker analysis using SSR (simple sequence repeat) markers in sunflower (Helianthus annuus). The document defines a complete SSR workflow - from sample preparation and DNA extraction to PCR amplification and fragment analysis - and supplies a validated set of 16 SSR markers (with primer sequences and allele size ranges) for use in hybrid conformity testing, molecular fingerprinting and variety identity checks.
Key topics and technical requirements
- Scope and purpose: Methods and SSR markers can be used for hybrid conformity testing, molecular fingerprinting of varieties and variety identity control.
- Sample preparation: Seed grinding using commercial grinders (examples provided) and aliquoting of homogenized material prior to DNA extraction.
- DNA extraction & quantification: Use of an internal protocol or equivalent (a QIAGEN DNeasy® 96 Plant Kit was used in interlaboratory work as an example). Laboratories must verify DNA quantity/quality suitable for reliable results.
- PCR amplification:
- Detailed PCR mix formulation (component volumes and concentrations are specified).
- A touchdown PCR program (annealing temperature reduced from 64 °C to 55 °C) is recommended; conditions were optimized for an ABI 9700 thermocycler.
- Marker set and primers: A list of 16 SSR markers (ORS/SSL series) with forward and reverse primer sequences, observed allele size ranges and Nei diversity indices based on validation data.
- Fragment analysis: Capillary electrophoresis with fluorescent detection (examples: 3130 Genetic Analyzer) is used to separate and size PCR products.
- Equipment & consumables: Microplates, thermocycler, capillary electrophoresis system, standard PCR reagents and labware are listed.
Practical applications and users
- Applications:
- Official hybrid conformity checks and seed certification.
- Molecular fingerprinting and variety characterization for breeding programs.
- Variety identity control in seed production, registration and market surveillance.
- Primary users:
- National and private seed testing laboratories.
- Plant breeders and variety registration authorities.
- Molecular biology labs involved in sunflower genetics and diversity studies.
- Regulatory bodies performing official controls of seed lots and hybrids.
Related standards
- ISO/TR 17622:2015 is linked to ISO 13495, which describes validation steps and acceptance criteria for such molecular methods. Development was carried out under ISO/TC 34/SC 16 (molecular biomarker methods).
Keywords: ISO/TR 17622:2015, SSR analysis, sunflower, molecular biomarker, simple sequence repeat, PCR, DNA extraction, capillary electrophoresis, molecular fingerprinting, hybrid conformity, variety identity.