*4.5. RNA Isolation and qRT-PCR*

RNA isolation and qRT-PCR analysis were performed as previously described [54]. Briefly, total RNA was isolated using the TRIzol Total RNA Isolation kit (Sangon Biotech, Shanghai, China) and treated with DNase I (Sangon Biotech, Shanghai, China). Eight hundred nanograms of total RNA was reverse-transcribed using RevertAid Premium Reverse Transcriptase (Thermo Fisher Scientific, Waltham, MA, USA) and diluted ten-fold for PCR amplification. The PCR was performed on a LightCycler480 II instrument (Roche, Basel, Switzerland). Each reaction contained 2 μL of cDNA template, 10 μL of SYBR Green qPCR Master Mix (BBI, Toronto, ON, Canada), and 0.2 μmol L−<sup>1</sup> gene-specific primers in a final volume of 20 μL. The PCR conditions included an initial incubation at 95 ◦C for 3 min, followed by 45 cycles of 95 ◦C for 5 s and 60 ◦C for 30 s. The specificity of the PCR reactions was determined by melting curve analyses of the products. Relative expression levels were calculated by the 2−ΔΔCT method. The rice *Actin1* gene was used as the internal control. The primer sequences are listed in Table S9.
