An optimised protocol for isolation of RNA through laser capture microdissection of leaf material

Laser Capture Microdissection is a powerful tool that allows thin slices of specific cells types to be separated from one another. However, the most commonly used protocol, which involves embedding tissue in paraffin wax, results in severely degraded RNA. Yields from low abundance cell types of leaves are particularly compromised. We reasoned that the relatively high temperature used for sample embedding, and aqueous conditions associated with sample preparation prior to microdissection contribute to RNA degradation. Here we describe an optimized procedure to limit RNA degradation that is based on the use of low melting point wax as well as modifications to sample preparation prior to dissection, and isolation of paradermal, rather than transverse sections. Using this approach high quality RNA suitable for down-stream applications such as quantitative reverse transcriptase polymerase chain reactions or RNA-sequencing is recovered from microdissected bundle sheath strands and mesophyll cells of leaf tissue.