Ethylene as a gas phytohormone plays significant roles in the whole life cycle of plant,ranging from growth and development to stress responses.A linear ethylene signaling pathway has been established in dicotyledonous model plant Arabidopsis.The ethylene signaling mechanism in rice is limited.Based on the distinct phenotype of root inhibition but coleoptile promotion in rice etiolated seedlings upon ethylene treatment,we isolated a set of rice ethylene-response mutants (mao huzi,mhz) and identified the corresponding genes through map-based cloning.Among these,MHZ7 and MHZ6 are similar to EIN2 and EIN3 in Arabidopsis.MHZ6/OsEIL1 and OsEIL2 regulate ethylene responses of roots and coleoptiles respectively.MHZ7,MHZ6/OsEIL1 and OsEIL2 negatively affect salt tolerance in rice seedlings.We further revealed novel interactions between ethylene and ABA in regulation of root and coleoptile growth.Ethylene can induce expression of MHZ5 (carotenoid isomerase) and MHZ4 (OsABA4) gene and drive the metabolic flux from carotenoid biosynthesis pathway to the ABA biosynthesis pathway to affect root growth.A few novel genes have been further identified and the possible functions were investigated and the relevant mechanism was discussed.Manipulation of the corresponding genes may help to improve stress tolerance and other agronomic traits in rice and/or other crops.