Regulation of Source–Sink Carbon Partitioning for Improving Rice Yield

Rice yield formation depends on the efficiency of photosynthetic carbon assimilation and its spatiotemporal partitioning into grains. Despite advances in identifying key genes and pathways, an integrated framework linking dynamic carbon flow regulation across source, sink, and vascular transport (flow) remains elusive. This article reviews recent insights into the physiological and molecular networks controlling source-sink carbon allocation and environmental response mechanisms in rice, emphasizing the crosstalk between sugar signaling (T6P-SnRK1), phytohormones, and transcriptional regulation. We further propose a carbon flow engineering framework that combines precision gene editing, growth regulator intervention, and climate-smart cultivation to synchronize carbon fixation, transport, and storage. This integrative approach provides novel targets for developing high-yielding, resource-efficient rice varieties resilient to environmental fluctuations.