Identification and Cloning of Tillering-Related Genes OsMAX1 in Rice

Tillering is an important agronomic trait which has a direct impact on plant type and grain yield. Strigolactones are a class of important phytohormones regulating rice tillering. ATMAX1 is an important gene involved in strigolactone biosynthesis through encoding the protein P450 in Arabidopsis. Based on sequence BLASTp, we identified five homologous genes of ATMAX1 in rice, i.e., OsMAX1a, OsMAX1b, OsMAX1c, OsMAX1d and OsMAX1e. Among them, OsMAX1a and OsMAX1e showed stable and high expression in rice tissues. In addition, we observed that OsMAX1a and OsMAX1e can rescue the branched phenotype and the influences caused by MAX1 mutation in Arabidopsis. Moreover, the expression of OsMAX1a and OsMAX1e can respond to phosphate deficiency and different phytohormones, especially GR24, a strigolactone analogue. Therefore, it is concluded that OsMAX1a and OsMAX1e are involved in the biosynthesis of strigolactones and regulated rice tillering.