LbCas12a-based DNA POCT facilitates fast genotyping on farm.

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a (CRISPR/Cas12a) detection system is now widely used for nucleic acid detection and disease diagnosis. However, there are still fewer detections for single nucleotide polymorphisms (SNPs) and limited diversified detection systems for pathogen and SNP sites detection, which greatly limits their applications. Obviously, the development of a more diversified and convenient suite of detection tools is essential to unlock the full potential of CRISPR/Cas12a technology and to expand its applications across a wider range of scenarios. We have successfully developed an integrated CRISPR/Cas12a assay system. This system introduces crRNA during protein expression, reducing the number of steps and reaction time by adding only a fluorescent reporter gene and target DNA during subsequent detection. It enables on-site visualization of the assay in combination with a Recombinase polymerase amplification (RPA) reaction. Combined with the RPA reaction, we are able to rapidly detect African swine fever virus (ASFV) pathogens with high specificity. The system also enables genotyping of the SNP site of the porcine prolificacy-associated estrogen receptor (ESR) gene and the sheep prolificacy-associated Fecundity booroola (FecB) gene. Visualization is possible up to a final concentration of 3 nM, and effective differentiation of low concentrations within the concentration range of the assay. The integrated CRISPR/Cas12a assay system we developed has a robust design that ensures high-fidelity genotyping and pathogen detection are no longer restricted to the lab, allowing for rapid field analysis, which is crucial for timely interventions in agricultural and clinical settings. In addition, it has the advantages of low cost, easy operation and visualization of results.