RESUMEN
The harm of plant virus disease is serious, which significantly restricts the sustainable development of agriculture and can cause huge economic losses. Monitoring plant health and early detection of viral pathogens are essential to reduce the spread of disease. Therefore, in order to realize the early detection of plant viral diseases in the field, a sensitive, specific and efficient colorimetric visual technique for plant viral RNA was designed by combining the colorimetric method based on gold nanoparticles (AuNPs) and hybrid chain reaction (HCR). In this study, tobacco mosaic virus (TMV) was used as a model to design two hairpin structures H1/ H2 with single-stranded tails based on TMV-specific conserved fragments. TMV could open the hairpin structure to alternately form long double-straight DNA. The binding difference between AuNPs and two nucleic acid states before and after HCR reaction resulted in colorimetric signal generation, thus realizing visual detection of TMV. After optimizing the concentration of Tris-HAc, the concentration of hairpin structure and the reaction time of HCR, the best detection conditions were obtained. The sensitivity and specificity of the technique were analyzed and real samples were tested under optimal conditions. The results showed that the absorbance ratio of AuNPs (A