Strigolactone Mediates Moso Bamboo Root Response to Phosphate Stress

Both phosphate (Pi) deficiency and high Pi significantly affect moso bamboo growth and degrade bamboo forests. A novel plant hormone, strigolactone (SL), plays a crucial role in root growth under low Pi, but the SL regulatory mechanism has not been systematically reported in moso bamboo. In our study, we investigated the SL-mediated root growth mechanism in response to Pi stress in moso bamboo. With the decrease of the Pi level, 5-deoxystrigol and strigol significantly increased in the root exudates. Transcriptome sequencing of the primary root tip and lateral root primordium zone (LRP) under low, sufficient, and high Pi indicated that SL-biosynthesis and -signaling changes are part of the early root responses. The effects of the SL analogue (rac-GR24) and SL inhibitor (TIS108) on the root architecture under low and high Pi revealed that SL mediates bamboo root responses by regulating its biosynthesis and signal transduction and influencing other hormone pathways.