Gene expression analysis
Various tissue samples of germinated seed, roots, leaf sheath, leaf blade, node, panicle, and immature seeds were harvested from different development stages (1-, 3-, and 16-week-old) of WT plants. To evaluate salinity stress induced changes in gene expression, 1-week-old seedlings were treated with 0 and 50 mM NaCl solution and root and tissue samples were harvested at 30 min, 1 h, 6h, and 24 h after treatment. Total RNA was extracted using TRIzol® reagent (Ambion, USA) and treated with DNAse I (Sigma-Aldrich) according to manufacturer’s instructions. One microgram of the total RNA was used to synthesize first strand cDNA using random oligomers. Real-time qPCR was performed using SYBR® Green TOP real qRT-PCR PreMIX (EnzynomicsTM, Daejeon, Korea), and the SYBR signals were monitored using a C1000 Thermal Cycler and CFX96 Real-Time System detection instrument (Bio-Rad Laboratories, USA). Expression levels of the OsMTP1 and selected marker genes (Lim et al., 2014) calculated using the 2-ΔΔCT method (Islam et al., 2017). OsActinII was used as an internal control (Livak & Schmittgen, 2001).