At the crossroads of botanical collections and molecular genetics laboratory: a preliminary study of obtaining amplifiable DNA from moss herbarium material.

Background: Research focused on extreme environments is often associated with difficulties in obtaining fresh plant material. Herbaria may provide great support as they house large collections of specimens from different parts of the world. Accordingly, there is also a growing interest in methods using herbarium specimens in molecular studies. Much of the literature on herbarium DNA is aimed to improve extraction and PCR amplification and is focused mostly on vascular plants. Here, I provide a brief study of DNA extraction efficiency from moss herbarium specimens, emphasizing the importance of herbaria as an invaluable source of material from hard-to-access geographical areas, such as the Antarctic region.

Methods: The presented study is based on herbarium collections of 25 moss species collected in the austral polar regions between 1979 and 2013. The majority of samples were obtained using the DNeasy Plant Mini Kit (Qiagen, Hilden, Germany). The remaining, smaller part was extracted using an adapted CTAB-based approach. The performance of DNA extraction methods in terms of PCR amplification success was measured by testing several DNA fragments of various size. Furthermore, in order to estimate of DNA fragmentation level, an automated on-chip electrophoresis system was used.

Results: Results reveal that DNA purity and the length of the target genetic region are the fundamental agents which drive the successful PCR reaction. Conversely, the DNA yield and specimen age seem to be less relevant. With this study, I present also an optimized CTAB-based approach which may effectively suppress inhibitors in the herbarium DNA. This method can be considered a cheaper alternative to column-based technology, particularly useful for dealing with a large number of samples. Results of this study confirmed previous reports and contribute to filling the existing gap in molecular analyses which involve the use of herbarium collections of mosses.