Development of Automated DNA and RNA Plant Extraction Kits Using the New Maxwell® RSC Platform

The wide diversity among plant taxa makes it difficult to find universal and robust solutions for extracting DNA and RNA. Poor and inconsistent extraction methods can carry over secondary compounds such as phenols and carbohydrates resulting in inaccurate quantification and inhibition of downstream amplification analyses. With this challenge in mind, Promega has developed an automated system that provides consistent DNA and RNA extraction from a variety of plant tissue samples.  The DNA extraction protocol was specifically optimized for purifying high molecular weight DNA, balancing the need for maximizing DNA yield per sample while minimizing multiple types of qPCR and next-generation sequencing inhibitors.  Likewise, the RNA extraction protocol was optimized to prevent degradation of RNA, improve purity, minimize RT-qPCR inhibitors, and maximize yield.  Both the RNA and DNA Plant kits require a minimal amount of sample input for the purification of high quality nucleic acids, compatible with all common downstream amplification-based assays.  While optimizing these protocols, we also discovered some advantages and pitfalls of various quantification methods that apply specifically to plant samples.  In some species, absorbance peaks in the 225-245 nm regions cause a drastic overestimation of the UV-based concentration estimation. As a consequence, performance of downstream applications may suffer due to incorrect input estimation.  We show that fluorescent dye-based quantification methods more accurately estimate nucleic acid concentration and correlate well with qPCR quantification.