The detection of a Cytochrome b gene (cytb) for species differentiation
in fish is intensively
used. A fast alternative to expensive and time-consuming DNA barcoding
is loop-mediated isothermal amplification (LAMP) in combination with
efficient readout systems. For this reason, we developed LAMP assays
for rapid species detection of Pleuronectes platessa and Solea solea, two economically
important flatfish species in Europe that are prone to mislabeling.
Species-specific primer sets targeting cytb were
designed, and LAMP assays were optimized. With the optimized LAMP
assays, we were able to detect up to 0.1 and 0.01 ng of target DNA
of P. platessa and S.
solea, respectively, and in each case up to 1% (w/w)
of target species in mixtures with nontarget species. For future on-site
detection, a lateral flow assay and a pocket-sized lab-on-phone assay
were used as readout systems. The lab-on-phone assay with the S. solea specific primer set revealed cross-reactivity
to Solea senegalensis. The assay targeting P. platessa proved to be highly specific. Both assays
could be performed within 45 min and provided rapid and easy detection
of fish species.