Rice (Oryza sativa L.) is one of the most important food crops in the world. Originating in tropical and subtropical regions, rice cultivars are grouped into two major subspecies, indica (O. sativa ssp. indica) and japonica (O. sativa ssp. japonica). indica cultivars grown in low latitude areas are sensitive to low temperature, while japonica cultivars with more resistance to cold temperature are grown in temperate and frigid zones. Low temperature is a major factor that affects rice production and distribution worldwide. Scientists have been making great efforts to identify genes that control chilling tolerance traits of rice. However, the molecular mechanism underlying the chilling adaptation of japonica is unknown.