Establishment of an RT ‐ LAMP ‐ CRISPR /Cas12a detection system for grapevine fabavirus and improvement of grapevine leaf crude extract with alkaline resin for on‐site naked‐eye detection

BACKGROUND: Grapevine fabavirus (GFabV) induces severe chlorosis and malformation in grapevine leaves, and its infection can substantially compromise both fruit yield and quality. Despite its growing impact on viticulture, no rapid and accurate on-site molecular diagnostic tool is currently available for the detection of GFabV. Thus, developing a reliable and field-deployable detection method is urgently needed. RESULTS: In this study, we designed six sets of primers targeting conserved regions of GFabV for loop-mediated isothermal amplification (LAMP), and identified one optimal primer set capable of detecting all three GFabV variants. To enhance assay specificity and enable instrument-free visual readout, LAMP and CRISPR/Cas12a were integrated to establish a real-time (RT)-LAMP-CRISPR/Cas12a single-tube assay. The established method demonstrated exceptional specificity and remarkable sensitivity, and it is ≤10 000 times more sensitive than conventional RT-PCR. We streamlined the RNA preparation process by replacing traditional RNA extraction with optimized crude extract protocols. For grapevine leaves, we developed a novel 'Alkaline Resin method', utilizing a newly engineered alkaline resin material that effectively neutralizes the acidic lysate while simultaneously adsorbing chlorophyll, polyphenols and polysaccharides. For grapevine branches, we introduced an extremely simple 'branch-washing method', wherein crude nucleic acids are obtained simply by rinsing the phloem tissue with water. By coupling crude extraction strategies with the RT-LAMP-CRISPR/Cas12a single-tube assay, we achieved on-site detection of GFabV within 50 min. CONCLUSION: We developed an RT-LAMP-CRISPR/Cas12a single-tube method, along with corresponding crude extraction procedures for grapevine branches and leaves, enabling simple, rapid, accurate and on-site detection of GFabV. © 2026 Society of Chemical Industry.