A mutation in OsPPDK impairs pyruvate phosphate dikinase activity, leading to floury endosperm in rice

Rice (Oryza sativa L.) is a crucial global food source, whose appearance quality affects its market value. In this study, a mutant, designated fe5, was generated from the Japonica cultivar Nipponbare via ethyl methane sulfonate (EMS) mutagenesis, which present floury endosperm compared to the wild type (WT). By map-based cloning, loc OsFE5 was located within a 103 kb region on the long arm of chromosome 5. Through whole-genome resequencing and Sanger sequencing between the WT and fe5 mutant, we confirmed that there was a T to C mutation in LOC_Os05g33570, leading to the change in amino acid from serine (S) to proline (P). The examination of grain quality metrics reveals a substantial reduction in amylose content in fe5 relative to the WT. The most crucial variation in the solubility of fe5 was noted at a 4 M urea concentration, reflecting alterations in the amylopectin structure of fe5 relative to the WT. Additionally, the gel consistency was elevated in fe5 in contrast to the WT. Our research yields novel genetic material, and the established molecular markers can be employed in marker-assisted breeding to improve endosperm characteristics in rice.

The online version contains supplementary material available at 10.1007/s11032-026-01659-4.