mRNA was purified from rice leaf blade as described by Suzuki et al. (2004). The total RNA was quantified by measuring the absorbance at 260 nm. The real-time PCR analysis was conducted using the StepOnePlus™ Real-Time PCR System (Applied Biosystems, USA) and Fast SYBR Green Master Mix (Life technologies Japan) (Ogawa et al., 2012). The primers used for mRNA expression analysis are listed in Table S1.