Optimizing efficient PCR-amplifiable DNA extraction from herbarium specimens

Abstract

Premise: The objective of this study was to optimize an existing DNA extraction protocol for recalcitrant plant taxa to obtain high-quality DNA from preserved herbarium tissue suitable for downstream PCR applications. Methods and Results: Leaf tissue from 30 diverse plant species was obtained from the U.S. National Arboretum Herbarium. Our previous DNA extraction protocol (Gouker et al., 2020, Applications in Plant Sciences 8: e11403) was improved by use of 10X Tris-EDTA buffer, addition of polyvinylpolypyrrolidone, and omission of sample heating during homogenization, and resulted in total DNA yields ranging from 60–2460 ng. Optimized PCR amplification using universal plant primers for the ITS-p3/u4 region and the P6 loop of the trnL (UAA) chloroplast intron was successful for most specimens. Conclusions: This protocol, which is simple, fast, and uses standard laboratory-grade chemicals, yields DNA from herbarium specimens that is comparable in quality to that from commercially available kits, and is of sufficient quality and quantity for other applications.