Metabolomics and transcriptomics analyses reveal quality differences in forage-grain ratoon rice under varying mowing...

The mechanisms underlying quality formation of forage-grain ratoon rice (FG-RR) were investigated using transcriptomics and metabolomics. Results revealed that mowing at milky-ripe stage (MS) significantly enhanced the percentages of brown rice, milled rice, and head rice compared to full-ripe stage (FRS), with increases of 2.37%, 2.40%, and 13.19%, respectively. Additionally, it had lower amylose and protein contents than FRS, decreasing by 8.09% and 26.28%. From heading stage to FRS, peak viscosity, fb₃ (DP ≥ 37) chain of amylopectin decreased, whereas gelatinization temperatures and fb₁ (DP 13-24) chain first increased and then decreased. Transcription levels of granule-bound starch synthase, starch branching enzymes, and starch isoamylase elevated during wax-ripe stage and FRS, resulting in the increased amylose content and altered amylopectin structure. Enhanced glycolysis, amino acid synthesis, and storage protein biosynthesis pathways contributed to increased protein content. MS mowing was more favourable for texture of cooked FG-RR, which provided a foundation for cultivating high-quality rice.