*4.7. RNA Extraction, Semi-Quantitative Real-Time PCR (RT-PCR), and Real-Time Quantitative PCR (qRT-PCR)*

Total RNA was extracted using Aidlab plant RNA kit (Aidlab Biotech, Beijing, China). The concentration and qualification were checked by NanoDrop™ One/OneC (ThermoFisher SCIENTIFIC, Waltham, MA, USA). Total RNA (1.0 µg) was used for first-strand cDNA synthesis using SuperScriptIII (Invitrogen), following the manufacturer's instructions. Gene-specific primers (Supplement Table S1) were designed by using Premier 5.0. qRT-PCR was performed on the Roche LightCycle 96 by using TB Green *Premix Ex Taq*II (TliRNaseH Plus) (RR420Q TaKaRa Biotechnology, Beijing, China), with a total sample volumeof 20 µL. The programs were 95 ◦C for 30 s, then 40 cycles of 95 ◦C for 5 s, and 65 ◦C for 34 s. The relative expression level was calculated while using the 2−∆∆CT method [48]. The *EgrEF* was used as the reference gene [49].
