SN/T 5132-2019 in English

Technical Background of the Standard

This standard was developed to meet the identification needs of Cistanche deserticola Ma and its closely related species, addressing the limitations of traditional morphological identification in dried medicinal materials. It was released and implemented in 2019, establishing for the first time an identification system combining molecular biology and morphology.

Comparison of core identification methods

Key morphological characteristics

Desert CistancheTypical characteristics that distinguish it from closely related species:

• Inflorescence: spike inflorescence 15-50cm long, 4-7cm in diameter
• Corolla: tubular, 3-4cm long, with 5 blue-purple lobes
• Bract: ovate, 1.5-2.7cm long, densely covered with hairs

Key points for molecular identification

DNA extraction

The sample DNA was extracted by CTAB method, and the OD260/280 value was required to be between 1.8-2.0 and the concentration was ≥50ng/μL.

PCR amplification

Use specific primer pairs:
Forward: 5′-ATGCGATACTTGGTGTGAAT-3′
Reverse: 5′-GACGCTTCTCAGACTACAAT-3′
Amplification program: 94℃ pre-denaturation for 3min; 35 cycles (94℃ 30s, 56℃ 30s, 72℃ 45s); 72℃ final extension for 10min.

Electrophoresis detection

1.0% agarose gel electrophoresis, run at 120V for 20min, the expected band size is about 650bp.

Suggestions for the implementation of the standard

1. Preferably use a stereomicroscope to observe the characteristics of bract hairs
2. The PCR reaction system needs to set up a negative control (ddH₂O) and a positive control (standard DNA)
3. ITS2 sequence needs to be submitted to the BOLD system for comparison and verification
4. When the morphological and molecular results conflict, the molecular identification results shall prevail

Analysis of technological evolution

Breakthroughs of this standard compared with traditional identification methods:

• For the first time, a dual verification system of morphology and molecular biology is integrated
• Introduction of ITS2 as the core barcode fragment
• Clearly differentiate between Cistanche deserticola (C. salsa), Discrimination threshold of Cistanche tubulosa(C. tubulosa)