OsPEX5 Regulates Rice Spikelet Development, Study Shows

Scientists from Nanjing Agricultural University in China reports that mutations in OSPEX5, which encodes a peroxisomal targeting sequence 1 (PTS1) receptor protein, cause formation of irregular spikelets. Their study is published in New Phytologist Trust.

Spikelet is the primary reproductive structure and a vital basis of grain yield in rice, however, the molecular mechanisms involved in rice spikelet development are still unclear. In the research conducted by Xiaoman You and colleagues, it was discovered that OSPEX5 can cooperate with OSOPR7, an enzyme vital in the production of jasmonic acid and for its transport into peroxisome, an organelle in the cytoplasm that plays an important role in the oxidation of biomolecules. The study showed that similar to plants with mutated Ospex5, the plants with inoperative OsOPR7 developed using CRISPR-Cas9 had lower concentrations of exogenous jasmonic acids and exhibited irregular spikelets. Application of exogenous jasmonic acid helped to partially correct the irregular formation of spikelets.

The findings indicate that OSPEX5 regulates spikelet development by causing the peroxisomal import of OsOPR7.

Read the summary of findings in New Phytologist Trust.