RNA Extraction and RT-PCR (SAIL_855_E09 and SAIL_1225_H06)

Total RNA was isolated from 3-d–old seedlings using the PureLink RNA Mini Kit (Invitrogen) according to the manufacturer’s instructions. Reverse transcription was performed with the iScript cDNA Synthesis Kit (Bio-Rad). The primers used for RT-PCR were TPX2F and TPX2R. The PP2A transcript was used as a positive control as described in Czechowski et al. (2005). PCR products that resulted from 35 amplification cycles were analyzed by agarose gel electrophoresis.