Amino acid transporter OsLAT1 negatively regulates tillering and yield by affecting amino acids and polyamines in rice

OsLAT1 exerts a negative influence on rice tillering and grain yield. OsLAT1 modulates rice growth by regulating the transport of amino acids and polyamines. OsLAT1 exhibits concentration-dependent effects on bud outgrowth and biomass accumulation. The L-type amino acid transporter (LAT) family facilitates the cellular transport of amino acids and polyamines. However, the functions of LAT transporters in rice remain insufficiently characterized. In this study, we identified a significant negative association between OsLAT1 transcript levels and tiller number in rice. Transcriptional analysis revealed that OsLAT1 is predominantly expressed in leaves, basal tissues, and panicles. Subcellular localization assays showed that the OsLAT1 protein is localized to the endoplasmic reticulum and is strongly induced by Asp), Leu, spermidine (Spd), and spermine (Spm). Furthermore, under hydroponic conditions, moderate concentrations of arginine (Arg) and serine (Ser) partially promoted bud outgrowth and biomass in OsLAT1 -overexpressing plants, whereas these effects diminished at higher Arg/Ser concentrations. In contrast, OsLAT1 facilitated the transport of spermidine (Spd) and spermine (Spm), thereby promoting axillary bud elongation and rice growth. These findings provide insights into amino acid transporter-mediated regulation of rice plant architecture and offer potential targets for yield improvement.