2. Academic Validation
  3. Light signal regulates endoreduplication and tomato fruit expansion through the SlPIF1a-SlTLFP8-SlCDKB2 module

Light signal regulates endoreduplication and tomato fruit expansion through the SlPIF1a-SlTLFP8-SlCDKB2 module

  • Proc Natl Acad Sci U S A. 2025 Jan 28;122(4):e2404445122. doi: 10.1073/pnas.2404445122.
Jiaojiao Zhang # 1 2,  Jiayi Xu # 1,  Xinman Wang 1 3,  Ying Liu 1,  Shuangtao Li 1 4,  Jialong Zhang 1,  Lingfeng He 1,  Luqin Guo 1 5,  Chonghua Li 1,  Xin-Xu Li 6,  Yang-Dong Guo 1,  Na Zhang 1
Affiliations

Affiliations

  • 1 Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China.
  • 2 Hebei Key Laboratory of Horticultural Germplasm Excavation and Innovative Utilization, College of Horticultural Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.
  • 3 Shanghai Key Laboratory of Facility Horticulture Technology, Facility Horticulture Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
  • 4 Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100093, China.
  • 5 Institute of Vegetables, Nanchong Academy of Agricultural Sciences, Nanchong, Sichuan 637000, China.
  • 6 Beijing Cuihu Agritech Co. Ltd., Beijing 100095, China.
  • # Contributed equally.
PMID: 39847324 DOI: 10.1073/pnas.2404445122
Abstract

Light serves as an energy source for cell division and expansion during fruit development. Cell expansion significantly influences fruit size and is closely linked to endoreduplication, a unique cell cycle variation characterized by DNA replication without cytokinesis. Paradoxically, under conditions of ample photosynthates, light signaling suppresses cell expansion. The intricate regulation of endoreduplication in response to light signaling during fruit development has remained an intriguing question. Here, our study revealed that Tubby-like F-box protein 8 (SlTLFP8) orchestrated endoreduplication to facilitate fruit cell expansion. As an Skp1-Cullin-F-box (SCF)-type E3 Ligase, SlTLFP8 promoted the ubiquitination and subsequent degradation of CYCLIN-DEPENDENT KINASE B2 (SlCDKB2), thereby elevating DNA ploidy. The light signaling component PHYTOCHROME-INTERACTING FACTOR 1a (SlPIF1a), identified as a pivotal negative regulator in the plant's light response, was found to directly interact with the promoter of the SlTLFP8 gene, thereby stimulating its transcriptional activation. Indeed, SlPIF1a contributed to a faster expansion rate of tomato fruit during nighttime. Altogether, our results elucidate the connection between light signals and fruit size regulation through endoreduplication.

Keywords

F-box tubby-like protein; cyclin-dependent kinase; fruit size; phytochrome-interacting factor; ubiquitination.

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