OsSTK-Mediated Sakuranetin Biosynthesis and Carbon Flux Orchestrate Growth and Defence in Rice

Plants balance resource energy allocation between growth and immunity to ensure survival and reproduction under limited availability. This study reveals that rice cultivars with elevated sucrose levels boost resistance to the fungal pathogen Magnaporthe oryzae by accumulating the phytoalexin sakuranetin, regulated by the transcription factor STOREKEEPER (OsSTK). OsSTK binds to the promoter region of OsNOMT (Naringenin-7-O-Methyltransferase) to drive sakuranetin biosynthesis. Rice overexpressing OsSTK exhibits enhanced resistance to M. oryzae and improved growth, with greater plant height and higher grain yield, achieved through optimised resource allocation and carbon flow supporting both primary and secondary metabolite production. Moreover, the identification of OsSTK haplotypes linked to functional divergence in sakuranetin-mediated resistance, particularly in high-sucrose rice cultivars, underscores OsSTK's capacity to overcome the traditional growth-defence trade-off. This work highlights OsSTK as a valuable molecular target for breeding resilient, high-yielding rice varieties capable of withstanding environmental stresses. By advancing our understanding of resource allocation through carbon flow regulation, this study offers a sustainable strategy to improve food security and promote agricultural resilience in the face of climate change.