Decoding the molecular 'terroir': Circular RNAs as stable environmental recorders for micro-geographical origin...

To address the persistent challenge of simply and accurately authenticating GI products against fraud from adjacent regions, this work employs an innovative molecular marker: circular RNA (circRNA). Following high-throughput sequencing of Beijing Pinggu Peach, we identified a panel of six circRNAs that were differentially expressed between the GI and adjacent non-GI regions. An OPLS-DA model built on these biomarkers achieved 100% accuracy in origin discrimination. Validation with samples from a subsequent harvest year confirmed the biomarker stability, with the model achieving over 97% accuracy. Mechanistic analysis suggested that these circRNAs function within a ceRNA network by sponging miRNAs (e.g., ppe-miR393, ppe-miR396) to mediate environmental adaptation and regulate fruit quality pathways. Their expression acted as a 'molecular recorder' of key environmental factors (altitude, daylight duration, and fruit calcium). This work establishes circRNA fingerprints as precise and stable biomarkers for micro-geographical traceability, providing a transformative, readily applicable tool for GI food protection.