Plant sample from Solanum tuberosum
RNA was isolated from microdissected cells with the PicoPure RNA isolation kit (Arcturus Engineering, Mountain View, CA, USA), incorporating an on-column treatment step with RNase-Free DNase (Qiagen, Valencia, CA, USA, Cat #79254).  Finally, RNA was quantified with an Agilent 2100 Bioanalyzer using reagents from the manufacturer’s RNA 6000 Pico kit and then stored at -80 °C. Purified RNAs were amplified using Ovation® RNA-Seq system (NuGEN). cDNA libraries were prepared using 2.0 µg of amplified cDNAs and sequenced at the DNA Facility, Iowa State University.