Identification of medicinal plants and plant sequences: multiplexed MLPA assay

Recognition of medicinal plant species or plant characters can be accomplished through the use of genomic DNA sequences unique to a species, a group of species, or a species variant. An assay well-suited to this application is the Multiplexed Ligase-dependent Probe Amplification (MLPA) assay. It uses the sensitivity of the polymerase chain reaction, but increases the specificity by including a key ligation step for those MLPA probes that hybridize to a DNA sequence. The MLPA can be used to perform multiple tests in one tube, but the number of tests is limited when the amplified products are separated by chromatography. The use of hybridization to a microarray as part of the MLPA allows for a potentially greater number of tests to be performed on one sample. We describe the method for the MLPA procedure in detail, including the microarray hybridization protocol.