RNA extraction and real-time PCR
Total RNA was prepared using Trizol reagent (Thermo Fisher, USA) according to the manufacturer’s instructions. RNA purity and concentration were measured using a spectrophotometer. One microgram of total RNA was reverse transcribed into cDNA using an RT Easy II First Strand cDNA Synthesis Kit (Roche, Cat#04379012001). Then, cDNA(18 ng) was amplified in a Real-Time PCR Easy (SYBR Green I) (MCE, Cat#HY-K0501) on Bio-Rad Sequence Detection system (Bio-Rad, USA). The following primers were listed in the supplementary table S1.