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.