Poly-adenine-Coupled LAMP Barcoding to Detect Apple Scar Skin Viroid

Area of Science:

• Plant pathology
• Molecular diagnostics
• Virology

Background:

• Apple Scar Skin Viroid (ASSVd) is a nonprotein coding, circular RNA pathogen.
• ASSVd is challenging to detect using traditional immunoassay methods.
• Accurate and rapid detection is crucial for preventing viroid spread in agriculture.

Purpose of the Study:

• To develop a highly sensitive and selective diagnostic assay for ASSVd detection in plants.
• To improve upon existing immunoassay limitations for viroid identification.
• To create a method suitable for rapid, field-based viroid diagnosis.

Main Methods:

• A one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was optimized for ASSVd detection.
• Loop primers were utilized to accelerate the RT-LAMP reaction.
• Real-time LAMP and melting curve analysis were employed for specificity.
• Gold nanoparticle (AuNP) barcoding with poly-adenine (A10) was integrated for colorimetric detection.

Main Results:

• The optimized ASSVd RT-LAMP assay demonstrated high sensitivity, with a detection limit of 10^4 copies of cDNA-ASSVd within 30 minutes.
• Real-time LAMP and melting curve analysis effectively distinguished true positives from nonspecific amplification.
• The AuNP barcoding assay exhibited high authentication capacity through visible colorimetric changes.
• The assay provides a potential alternative for rapid and multiple viroid diagnoses.

Conclusions:

• The developed RT-LAMP assay offers a sensitive, selective, and rapid method for ASSVd detection in plants.
• The integration of colorimetric barcoding allows for visible sensing, suitable for field applications.
• This assay has the potential to aid in the development of viroid-free planting materials and disease management strategies.