Optimization of DNA extraction and PCR protocols for phylogenetic analysis in Schinopsis spp. and related Anacardiaceae

The Anacardiaceae is an important and worldwide distributed family of ecological and socio-economic relevance. Notwithstanding that, molecular studies in this family are scarce and problematic because of the particularly high concentration of secondary metabolites-i.e. tannins and oleoresins-that are present in almost all tissues of the many members of the group, which complicate the purification and amplification of the DNA. The objective of this work was to improve an available DNA isolation method for Schinopsis spp. and other related Anacardiaceae, as well as the PCR protocols for DNA amplification of the chloroplast trnL-F, rps16 and ndhF and nuclear ITS-ETS fragments. The modifications proposed allowed the extraction of 70-120 µg of non-degraded genomic DNA per gram of dry tissue that resulted useful for PCR amplification. PCR reactions produced the expected fragments that could be directly sequenced. Sequence analyses of amplicons showed similarity with the corresponding Schinopsis accessions available at GenBank. The methodology presented here can be routinely applied for molecular studies of the group aimed to clarify not only aspects on the molecular biology but also the taxonomy and phylogeny of this fascinating group of vascular plants.