Manipulating osa-MIR156f Expression by D18 Promoter to Regulate Plant Architecture and Yield Traits both in Seasonal and Ratooning Rice.

BACKGROUND: Rice (Oryza sativa L.) feeds more than half of the world's population. Ratooning rice is an economical alternative to the second seasonal rice, thus increasing the yield of ratooning rice is highly important. RESULTS: Here we report an applicable transgenic line constructed through the manipulation of osa-MIR156f expression in rice shoot using the OsGA3ox2 (D18) promoter. In seasonal rice, the D18-11 transgenic line showed moderate height and more effective tillers with normal panicle. In ratooning rice, axillary buds outgrew from the basal node of the D18-11 transgenic line before the harvest of seasonal rice. More effective tillers produced by the outgrowth of axillary buds contributed to the plant architecture improvement and yield increase. Additionally, it was found that osa-miR156f down-regulated the expression of tillering regulators, such as TEOSINTE BRANCHED1 (TB1) and LAX PANICLE 1 (LAX1). The expression of DWARF10, DWARF27 and DWARF53, three genes being involved in the biosynthesis and signaling of strigolactone (SL), decreased in the stem of the D18-11 transgenic line. CONCLUSION: Our results indicated that the manipulation of osa-MIR156f expression may have application significance in rice genetic breeding. This study developed a novel strategy to regulate plant architecture and grain yield potential both in the seasonal and ratooning rice.