Fig. 1

Screening of P. multocida RPA-LFD primers and LF-probe. a The results of an RPA-nfo reaction for three primer set and LF-probe combination were detected by agarose-gel electrophoresis (lane 1: F1-R, 192 bp; lane 2: F2-R, 189 bp; F3-R, 179 bp; LF-R, 150 bp; M: molecular weight standard DNA marker 1000); b ‘+’ showed the results of the RPA-nfo reaction by LFD test, the DNA template was derived from 6 × 10⁴ copies/μl standard DNA, and ‘NC’ was the negative control for the corresponding combination of primers and probe. c Optimisation of RPA reaction temperature. The results were positive for reactions performed in temperatures between 35 and 50 °C. d Evaluation of amplification time. After a 15-min amplification reaction, the test positive line was clearly visible on the test strip. Lane NC: negative control. Each sample was independently tested three times and one reaction was displayed