Abstract
To over-top the neighbors, shade-intolerant plants trigger shade avoidance responses with increasing the elongation of stem-like organs at the expense of leaf development. Shade-induced elongation growth has been extensively studied, while the regulatory mechanisms underlying shade-suppressed leaf development remain poorly understood. Here we find sucrose can rescue shade-inhibited leaf development, which requires the functions of phytochrome A (phyA) and TARGET OF RAPAMYCIN (TOR) complex. We confirm an interaction between PHYA and LETHAL WITH SEC THIRTEEN 8 (LST8), a component of TOR complex. Shade and phyA affect TOR activity, in turn TOR affects the protein stability of PHYA. The sucrose–TOR mediated accumulation of PHYA requires CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)/SUPPRESSOR OF PHYA-105 (SPA) complex. Transcriptome analysis further reveals that sucrose and phyA regulate the expression of leaf development-related genes under shade, particularly those involved in cytokinin metabolism. Our work uncovers a critical role for TOR and PHYA in linking light signaling with cellular energy status, a mechanism that fine-tunes leaf development specifically under shade conditions.
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Data availability
The raw and processed RNA-seq data generated in this study were deposited in the NCBI GEO database under accession code GSE291348. Previously published RNA-seq datasets used in this study are available in the NCBI GEO database under accession numbers GSE17845 and GSE104146. Phosphoproteomic data were deposited in the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PRIDE: PXD075951. Source data are provided with this paper (https://doi.org/10.6084/m9.figshare.30879302).
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Acknowledgments
The work was supported by the National Natural Science Foundation of China (32030018) to L.L. We thank Prof. Yan Xiong (Fujian Agriculture and Forestry University, Fujian, China) for sharing plant materials tor-es, pCYCB1;1::GUS and the valuable anti-TOR antibody. We also thank Prof. Jizong Wang (Peking University, Beijing, China) for sharing the purified AtphyA protein.
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J.W., F.L., and L.L. designed the experiments. J.W., F.L., and C.L. performed the experiments. L.L wrote the paper.
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Wang, J., Li, F., Lu, C. et al. Sucrose-activated TOR and phyA signaling alleviates shade-mediated inhibition of leaf development in Arabidopsis. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71841-x
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DOI: https://doi.org/10.1038/s41467-026-71841-x
