RNA extraction and RT-qPCR
Total RNA was isolated using TRIzol reagent (Invitrogen) according to the manufacturer’s instructions. RNA quantity and purity were assessed with NanoQuant spectrophotometer. First strand cDNAs were synthesized from DNase I-treated total RNA using cDNA Synthesis Kit (Takara). Gene expression was normalized using tubulin (At5g23860) as the reference gene, and relative gene expression was calculated as the mean of three biological replicates and three technical replicates. Gene specific primers used for RT-qPCR are listed in Table S1.