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Photoperiod controls plant seed size in a CONSTANS-dependent manner

Nature Plants volume 9, pages 343–354 (2023)Cite this article

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Abstract

Photoperiodic plants perceive changes in day length as seasonal cues to orchestrate their vegetative and reproductive growth. Although it is known that the floral transition of photoperiod-sensitive plants is tightly controlled by day length, how photoperiod affects their post-flowering development remains to be clearly defined, as do the underlying mechanisms. Here we demonstrate that photoperiod plays a prominent role in seed development. We found that long-day (LD) and short-day (SD) plants produce larger seeds under LD and SD conditions, respectively; however, seed size remains unchanged when CONSTANS (CO), the central regulatory gene of the photoperiodic response pathway, is mutated in Arabidopsis and soybean. We further found that CO directly represses the transcription of AP2 (a known regulatory gene of seed development) under LD conditions in Arabidopsis and SD conditions in soybean, thereby controlling seed size in a photoperiod-dependent manner, and that these effects are exerted through regulation of the proliferation of seed coat epidermal cells. Collectively, our findings reveal that a crucial regulatory cascade involving CO-AP2 modulates photoperiod-mediated seed development in plants and provide new insights into how plants with different photoperiod response types perceive seasonal changes that enable them to optimize their reproductive growth.

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Fig. 1: Seed size determination of various plant species grown under LDs and SDs.
Fig. 2: CO mediates photoperiod-regulated seed size in Arabidopsis.
Fig. 3: The expression patterns of CO in developing Arabidopsis seeds.
Fig. 4: CO directly inhibits the transcription of AP2.
Fig. 5: CO controls epidermal cell proliferation of seed coat through AP2.
Fig. 6: GmCOL2b-GmAP2s mediates photoperiod-regulated seed size in soybean.
Fig. 7: A hypothetical model of photoperiod controlling seed size.

Data availability

The data that support the findings of this study are available from the corresponding authors upon request. The high-throughput sequencing data performed in this study were deposited in the NCBI Gene Expression Omnibus database with the accession numbers PRJNA827694 and PRJNA896767. Source data are provided with this paper.

References

  1. Shim, J. S., Kubota, A. & Imaizumi, T. Circadian clock and photoperiodic flowering in Arabidopsis: CONSTANS is a hub for signal integration. Plant Physiol. 173, 5–15 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  2. Johansson, M. & Staiger, D. Time to flower: interplay between photoperiod and the circadian clock. J. Exp. Bot. 66, 719–730 (2015).

    Article  CAS  PubMed  Google Scholar 

  3. Martínez-García, J. F., Virgós-Soler, A. & Prat, S. Control of photoperiod-regulated tuberization in potato by the Arabidopsis flowering-time gene Constans. Proc. Natl Acad. Sci. USA 99, 15211–15216 (2002).

    Article  PubMed  PubMed Central  Google Scholar 

  4. Nomoto, Y. et al. Circadian clock- and PIF4-controlled plant growth: a coincidence mechanism directly integrates a hormone signaling network into the photoperiodic control of plant architectures in Arabidopsis thaliana. Plant Cell Physiol. 53, 1950–1964 (2012).

    Article  CAS  PubMed  Google Scholar 

  5. Hassidim, M. & Dakhiya, Y. CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and the circadian control of stomatal aperture. Plant Physiol. 175, 1864–1877 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Farré, E. M. & Weise, S. E. The interactions between the circadian clock and primary metabolism. Curr. Opin. Plant Biol. 15, 293–300 (2012).

    Article  PubMed  Google Scholar 

  7. Fonseca, J. P. & Dong, X. Functional characterization of a Nudix hydrolase AtNUDX8 upon pathogen attack indicates a positive role in plant immune responses. PLoS ONE 9, e114119 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  8. Greenham, K. & McClung, C. R. Integrating circadian dynamics with physiological processes in plants. Nat. Rev. Genet. 16, 598–610 (2015).

    Article  CAS  PubMed  Google Scholar 

  9. Li, M. et al. Comprehensive mapping of abiotic stress inputs into the soybean circadian clock. Proc. Natl Acad. Sci. USA 116, 23840–23849 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  10. Sanchez, A., Shin, J. & Davis, S. J. Abiotic stress and the plant circadian clock. Plant Signal. Behav. 6, 223–231 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Garner, W. W. & Allard, H. A. Effect of the relative length of day and night and other factors of the environment on growth and reproduction in plants. Mon. Weather Rev. 48, 415 (1920).

    Article  Google Scholar 

  12. Lin, X. et al. Molecular mechanisms for the photoperiodic regulation of flowering in soybean. J. Integr. Plant Biol. 63, 981–994 (2021).

    Article  CAS  PubMed  Google Scholar 

  13. Kantolic, A. G. & Slafer, G. A. Reproductive development and yield components in indeterminate soybean as affected by post-flowering photoperiod. Field Crops Res. 93, 212–222 (2005).

    Article  Google Scholar 

  14. Kantolic, A. G., Peralta, G. E. & Slafer, G. A. Seed number responses to extended photoperiod and shading during reproductive stages in indeterminate soybean. Eur. J. Agron. 51, 91–100 (2013).

    Article  Google Scholar 

  15. Nico, M., Miralles, D. J. & Kantolic, A. G. Post-flowering photoperiod and radiation interaction in soybean yield determination: direct and indirect photoperiodic effects. Field Crops Res. 176, 45–55 (2015).

    Article  Google Scholar 

  16. Nico, M. et al. Soybean fruit development and set at the node level under combined photoperiod and radiation conditions. J. Exp. Bot. 67, 365–377 (2016).

    Article  CAS  PubMed  Google Scholar 

  17. Cao, J. et al. Into the seed: auxin controls seed development and grain yield. Int. J. Mol. Sci. 21, e1662 (2020).

    Article  Google Scholar 

  18. Zhang, B. et al. Mobile TERMINAL FLOWER1 determines seed size in Arabidopsis. Nat. Plants 6, 1146–1157 (2020).

    Article  CAS  PubMed  Google Scholar 

  19. Zhou, Y. et al. SHORT HYPOCOTYL UNDER BLUE1 associates with MINISEED3 and HAIKU2 promoters in vivo to regulate Arabidopsis seed development. Plant Cell 21, 106–117 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Li, N., Xu, R. & Li, Y. Molecular networks of seed size control in plants. Annu. Rev. Plant Biol. 70, 435–463 (2019).

    Article  CAS  PubMed  Google Scholar 

  21. Garcia, D., Gerald, J. N. F. & Berger, F. Maternal control of integument cell elongation and zygotic control of endosperm growth are coordinated to determine seed size in Arabidopsis. Plant Cell 17, 52–60 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  22. Schruff, M. C. et al. The AUXIN RESPONSE FACTOR 2 gene of Arabidopsis links auxin signalling, cell division, and the size of seeds and other organs. Development 133, 251–261 (2006).

    Article  CAS  PubMed  Google Scholar 

  23. Ohto, M. et al. Control of seed mass by APETALA2. Proc. Natl Acad. Sci. USA 102, 3123–3128 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Jofuku, K. D. et al. Control of seed mass and seed yield by the floral homeotic gene APETALA2. Proc. Natl Acad. Sci. USA 102, 3117–3122 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Kunst, L. et al. AP2 gene determines the identity of perianth organs in flowers of Arabidopsis thaliana. Plant Cell 1, 1195–1208 (1989).

    Article  PubMed  PubMed Central  Google Scholar 

  26. Ohto, M. A. et al. Effects of APETALA2 on embryo, endosperm, and seed coat development determine seed size in Arabidopsis. Sex. Plant Reprod. 22, 277–289 (2009).

    Article  PubMed  PubMed Central  Google Scholar 

  27. Kang, X. et al. A WRKY transcription factor recruits the SYG1-like protein SHB1 to activate gene expression and seed cavity enlargement. PLoS Genet. 9, e1003347 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  28. Luo, M. et al. MINISEED3 (MINI3), a WRKY family gene, and HAIKU2 (IKU2), a leucine-rich repeat (LRR) KINASE gene, are regulators of seed size in Arabidopsis. Proc. Natl Acad. Sci. USA 102, 17531–17536 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  29. Wigge, P. A. et al. Integration of spatial and temporal information during floral induction in Arabidopsis. Science 309, 1056–1059 (2005).

    Article  CAS  PubMed  Google Scholar 

  30. Yamaguchi, A. et al. TWIN SISTER OF FT (TSF) acts as a floral pathway integrator redundantly with FT. Plant Cell Physiol. 46, 1175–1189 (2005).

    Article  CAS  PubMed  Google Scholar 

  31. Luccioni, L. et al. CONSTANS delays Arabidopsis flowering under short days. Plant J. 97, 923–932 (2019).

    Article  CAS  PubMed  Google Scholar 

  32. Yano, M. et al. Hd1, a major photoperiod sensitivity quantitative trait locus in rice, is closely related to the Arabidopsis flowering time gene CONSTANS. Plant Cell 12, 2473–2484 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. Ishikawa, R. et al. Phytochrome B regulates Heading date 1 (Hd1)-mediated expression of rice florigen Hd3a and critical day length in rice. Mol. Genet. Genom. 285, 461–470 (2011).

    Article  CAS  Google Scholar 

  34. Nemoto, Y. et al. Hd1, a CONSTANS ortholog in rice, functions as an Ehd1 repressor through interaction with monocot-specific CCT-domain protein Ghd7. Plant J. 86, 221–233 (2016).

    Article  CAS  PubMed  Google Scholar 

  35. Cao, D. et al. GmCOL1a and GmCOL1b function as flowering repressors in soybean under long-day conditions. Plant Cell Physiol. 12, 2409–2422 (2015).

    Article  Google Scholar 

  36. Wu, F. et al. Functional and evolutionary characterization of the CONSTANS gene family in short-day photoperiodic flowering in soybean. PLoS ONE 9, e85754 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  37. Suárez-López, P. et al. CONSTANS mediates between the circadian clock and the control of flowering in Arabidopsis. Nature 410, 1116–1120 (2001).

    Article  PubMed  Google Scholar 

  38. An, H. et al. CONSTANS acts in the phloem to regulate a systemic signal that induces photoperiodic flowering of Arabidopsis. Development 131, 3615–3626 (2004).

    Article  CAS  PubMed  Google Scholar 

  39. Hayama, R. et al. PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length. EMBO J. 36, 904–918 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Lv, X. et al. Structural insights into the multivalent binding of the Arabidopsis FLOWERING LOCUS T promoter by the CO-NF-Y master transcription factor complex. Plant Cell 33, 1182–1195 (2021).

    Article  PubMed  Google Scholar 

  41. Fan, C. et al. Conserved CO-FT regulons contribute to the photoperiod flowering control in soybean. BMC Plant Biol. 14, e9 (2014).

    Article  Google Scholar 

  42. Wu, F. et al. Transcriptome-enabled network inference revealed the GmCOL1 feed-forward loop and its roles in photoperiodic flowering of soybean. Front. Plant Sci. 10, 1221 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  43. Jiang, W. et al. Genome-wide identification and characterization of APETALA2/Ethylene-responsive element binding factor superfamily genes in soybean seed development. Front. Plant Sci. 11, 1348 (2020).

    Article  Google Scholar 

  44. Lu, S. et al. Stepwise selection on homeologous PRR genes controlling flowering and maturity during soybean domestication. Nat. Genet. 52, 428–436 (2020).

    Article  CAS  PubMed  Google Scholar 

  45. Li, X. et al. Overcoming the genetic compensation response of soybean florigens to improve adaptation and yield at low latitudes. Curr. Biol. 31, 3755–3767 (2021).

    Article  CAS  PubMed  Google Scholar 

  46. He, H. et al. Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis. J. Exp. Bot. 65, 6603–6615 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  47. Song, J. et al. Isolation and mapping of a family of putative zinc-finger protein cDNAs from rice. DNA Res. 5, 95–101 (1998).

    Article  CAS  PubMed  Google Scholar 

  48. Griffiths, S. et al. The evolution of CONSTANS-like gene families in barley, rice, and Arabidopsis. Plant Physiol. 131, 1855–1867 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Chia, T. Y. et al. Sugar beet contains a large CONSTANS-LIKE gene family including a CO homologue that is independent of the early-bolting (B) gene locus. J. Exp. Bot. 59, 2735–2748 (2005).

    Article  Google Scholar 

  50. Hayama, R. et al. A circadian rhythm set by dusk determines the expression of FT homologs and the short-day photoperiodic flowering response in Pharbitis. Plant Cell 19, 2988–3000 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Wong, A. C. et al. Isolation and functional analysis of CONSTANS-LIKE genes suggests that a central role for CONSTANS in flowering time control is not evolutionarily conserved in Medicago truncatula. Front. Plant Sci. 5, 486 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  52. Schmid, M. et al. A gene expression map of Arabidopsis thaliana development. Nat. Genet. 37, 501–506 (2005).

    Article  CAS  PubMed  Google Scholar 

  53. Zhang, X. et al. TaCol-B5 modifies spike architecture and enhances grain yield in wheat. Science 376, 180–183 (2022).

    Article  CAS  PubMed  Google Scholar 

  54. Serrano-Bueno et al. Regulation of floral senescence in Arabidopsis by coordinated action of CONSTANS and jasmonate signaling. Mol. Plant 15, 1710–1724 (2022).

    Article  CAS  PubMed  Google Scholar 

  55. Liu, L. et al. Post-fertilization expression of FLOWERING LOCUS T suppresses reproductive reversion. Front. Plant Sci. 5, 164 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  56. Onouchi, H. et al. Mutagenesis of plants overexpressing CONSTANS demonstrates novel interactions among Arabidopsis flowering-time genes. Plant Cell 12, 885–900 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  57. Valverde, F. et al. Photoreceptor regulation of CONSTANS protein in photoperiodic flowering. Science 303, 1003–1006 (2004).

    Article  CAS  PubMed  Google Scholar 

  58. Ho, L. Metabolism and compartmentation of imported sugars in sink organs in relation to sink strength. Annu. Rev. Plant Biol. 39, 355–378 (1988).

    Article  CAS  Google Scholar 

  59. Ortiz-Marchena, M. I. et al. Photoperiodic control of carbon distribution during the floral transition in Arabidopsis. Plant Cell 26, 565–584 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  60. Andrés, F. et al. The sugar transporter SWEET10 acts downstream of FLOWERING LOCUS T during floral transition of Arabidopsis thaliana. BMC Plant Biol. 20, 53 (2020).

    Article  PubMed  PubMed Central  Google Scholar 

  61. Wei, X. et al. The distribution of japonica rice cultivars in the lower region of the Yangtze river valley is determined by its photoperiod-sensitivity and heading date genotypes. J. Integr. Plant Biol. 51, 922–932 (2009).

    Article  PubMed  Google Scholar 

  62. Guo, Z. et al. Discovery, evaluation and distribution of haplotypes of the wheat Ppd-D1 gene. New Phytol. 185, 841–851 (2010).

    Article  CAS  PubMed  Google Scholar 

  63. Faure, S. et al. Mutation at the circadian clock gene EARLY MATURITY 8 adapts domesticated barley (Hordeum vulgare) to short growing seasons. Proc. Natl Acad. Sci. USA 109, 8328–8333 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  64. Lee, C. et al. Genetic interactions reveal the antagonistic roles of FT/TSF and TFL1 in the determination of inflorescence meristem identity in Arabidopsis. Plant J. 99, 452–464 (2019).

    Article  CAS  PubMed  Google Scholar 

  65. Balasubramanian, S. et al. Potent induction of Arabidopsis thaliana flowering by elevated growth temperature. PLoS Genet. 2, e106 (2006).

    Article  PubMed  PubMed Central  Google Scholar 

  66. Simon, R., Lsabellgeno, M. & Coupland, G. Activation of floral meristem identity genes in Arabidopsis. Nature 384, 59–62 (1996).

    Article  CAS  PubMed  Google Scholar 

  67. Samach, A. et al. Distinct roles of CONSTANS target genes in reproductive development of Arabidopsis. Science 288, 1613–1616 (2000).

    Article  CAS  PubMed  Google Scholar 

  68. Hu, Y. et al. Gibberellins play an essential role in late embryogenesis of Arabidopsis. Nat. Plants 4, 289–298 (2018).

    Article  CAS  PubMed  Google Scholar 

  69. Li, C. et al. Site-specific phosphorylation of TRANSPARENT TESTA GLABRA1 mediates carbon partitioning in Arabidopsis seeds. Nat. Commun. 9, 571 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  70. Li, N. et al. The rice tapetum degeneration retardation gene is required for tapetum degradation and anther development. Plant Cell 18, 2999–3014 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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Acknowledgements

We thank Z. Dong of Guangzhou University for providing Arabidopsis seeds of different ecotypes. This work was supported by grants from Key Deployment Project of Chinese Academy of Sciences (ZDRW-ZS-2019-2 to X.H.), the National Natural Science Foundation of China (31871643 to X.H. and 31900212 to Y.H.), and the ‘Strategic Priority Research Program’ of the Chinese Academy of Sciences (XDA24010100 to X.H.).

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  1. These authors contributed equally: Bin Yu, Xuemei He, Yang Tang.

Authors and Affiliations

  1. Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China

    Bin Yu, Xuemei He, Zhonghui Chen, Limeng Zhou, Xiaoming Li, Chunyu Zhang, Xiang Huang, Yuhua Yang, Wenbin Zhang, Xingliang Hou & Yilong Hu

  2. University of the Chinese Academy of Sciences, Beijing, China

    Bin Yu, Xuemei He, Zhonghui Chen, Limeng Zhou, Xiaoming Li, Chunyu Zhang, Xiang Huang, Yuhua Yang, Wenbin Zhang, Xingliang Hou & Yilong Hu

  3. Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, Guangzhou Key Laboratory of Crop Gene Editing, Innovative Center of Molecular Genetics and Evolution, School of Life Sciences, Guangzhou University, Guangzhou, China

    Yang Tang & Fanjiang Kong

  4. School of Biological Sciences, Nanyang Technological University, Singapore, Singapore

    Yansong Miao

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Contributions

Y.H. and X. Hou conceived and designed the project. B.Y., X. He, Y.T., Z.C., L.Z., X.L., C.Z., X. Huang, Y.Y. and W.Z. conducted the experiments. B.Y., X. He, Y.T., F.K., Y.M. and Z.C analysed the data. B.Y., X. He, X. Hou and Y.H. wrote the manuscript.

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Correspondence to Xingliang Hou or Yilong Hu.

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Nature Plants thanks Federico Valverde, Keqiang Wu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Flowering time and seed mass determination of various plant species grown under LDs and SDs.

a, Flowering time of various plants grown under LDs and SDs. DBF, days before flowering. Data are presented as means ± s.d. of 10 biological replicates. b, Hundred-seed mass of various plants grown under LDs and SDs. Seed mass is the average value of five sample batches with each containing 100 seeds. Data are presented as means ± s.d. of 5 biological replicates. Asterisks indicate significant difference compared with plants grown under LDs (two-tailed Student’s t-test, *P < 0.05, **P < 0.01). All exact P values are shown in Source Data Extended Data Fig. 1.

Source data

Extended Data Fig. 2 Flowering time and seed mass determination of various Arabidopsis ecotypes grown under LDs and SDs.

a, Flowering time of various Arabidopsis ecotypes grown under LDs and SDs. Data are presented as means ± s.d. of 10 biological replicates. b, Thousand-seed mass of various Arabidopsis ecotypes grown under LDs and SDs. Seed mass is the average value of five sample batches with each containing 1000 seeds. Data are presented as means ± s.d. of 5 biological replicates. Asterisks indicate significant difference compared with plants grown under LDs (two-tailed Student’s t-test, **P < 0.01). All exact P values are shown in Source Data Extended Data Fig. 2.

Source data

Extended Data Fig. 3 Phenotypes of various genetic materials of CO grown under LDs.

a, Comparison of representative 24-d-old plants with various genetic backgrounds grown under LDs. Scale bar, 5 cm. b, Flowering time of plants shown in a. Data are presented as means ± s.d. of 10 biological replicates. c, Plant stature of representative 60-d-old plants with various genetic backgrounds grown under LDs. Scale bar, 5 cm. d, Yield per plant of various genetic materials grown under LDs. Data are presented as means ± s.d. of 10 biological replicates. e, Comparison of representative 16 DAP siliques harvested from various genetic materials grown under LDs. Scale bar, 2 mm. f, Silique capacity per seed showing that big seeds occupy larger space than small seeds in siliques. The ratio was calculated by silique area against the seed number per silique in various genetic materials grown under LDs. Data are presented as means ± s.d. of 30 biological replicates. g, Comparison of dry mature seeds of various genetic materials grown under LDs. Scale bar, 500 µm. h, Seed size statistics of various genetic materials shown in g. Data are presented as means ± s.d. of 50 biological replicates. Different lowercase letters above the columns indicate the significant difference among different groups (one-way ANOVA, Tukey post-test, P < 0.05). All exact P values are shown in Source Data Extended Data Fig. 3.

Source data

Extended Data Fig. 4 CO acts as the central regulator of photoperiod response pathway to promote flowering transition in Arabidopsis.

CO acts as the central regulator of photoperiod response pathway to integrate external and internal signals into the photoperiodic flowering pathway. The transcription and protein abundance of CO is tightly controlled by circadian clock and intrinsic clues for proper FLOWERING LOCUS T (FT) induction that triggers flowering transition. CO can also inhibit flowering by disordering the expression pattern of TERMINAL FLOWER 1 (TFL1), which functions antagonistic to FT. Photoperiod-dependent patterns of CO transcript abundance are tightly controlled by the FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1)-GIGANTEA (GI) complex, which mediates the degradation of CO transcriptional repressors known as CYCLING DOF FACTORs (CDFs). Degradation of CDFs facilitates access by transcriptional activators FLOWERING BHLHS (FBHs) to the CO promoter. Several kinds of photoreceptors, including FKF1, phytochrome A (phyA) and cryptochromes (CRYs), are involved in CO protein stabilization. Other factors, including phytochrome B (phyB), HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 (HOS1), and CONSTITUTIVELY PHOTOMORPHOGENIC1 -SUPPRESSOR OF PHYTOCHROME A (COP1-SPA) complexes, are involved in the degradation of CO protein.

Extended Data Fig. 5 Photoperiod affects seed size independent of accumulative radiation.

Seed area of Col-0, 35S:CO, and co-9 grown under LDs-LDs, LDs-dSDs, and LDs-SDs. LDs-LDs, plants were grown under LDs until harvest; LDs-dSDs, plants were grown under LDs until bolting and then transferred to SD conditions under a double of normal light intensity; LDs-SDs, plants were grown under LDs until bolting and then transferred to SDs. Data are presented as means ± s.d. of 100 biological replicates. Different lowercase letters above the columns indicate the significant difference among different groups (one-way ANOVA, Tukey post-test, P < 0.05). All exact P values are shown in Source Data Extended Data Fig. 5.

Source data

Extended Data Fig. 6 CO functions in early stage of seed development under LDs.

a, Representative unfertilized mature ovules of Col-0 and co-9 plants. Scale bar, 50 µm. b, Area of unfertilized mature ovules in Col-0 and co-9 plants. Data are presented as means ± s.d. of 10 biological replicates. c, Seed area of wild-type (Ler) and co-2 35S:CO-GR (CO-GR) treated with 10 μM Dex or mock. Different stages of silique at 2, 4, 6, 8 or 10 DAP were chosen for the first-time treatment, respectively, then once every 3 d until reaching maturity. Data are presented as means ± s.d. of 100 biological replicates. Different lowercase letters above the columns indicate the significant difference among different groups (one-way ANOVA, Tukey post-test, P < 0.05). All plants were grown under LDs. All exact P values are shown in Source Data Extended Data Fig. 6.

Source data

Extended Data Fig. 7 The CO expression in developing Arabidopsis siliques and seeds.

a, GUS staining in developing siliques in pCO:GUS. Scale bar, 2 mm. b, Partial enlarged detail of GUS staining in 8 DAP siliques. Scale bar, 100 μm. CZSC, chalazal seed coat; H, hilum; SW, silique wall. All plants were grown under LDs.

Extended Data Fig. 8 gCO-3FLAG completely rescues the phenotype of co-9.

a–c, Flowering time, seed area and seed mass of Col-0, co-9 and 3 representative co-9 gCO-3FLAG lines (#1-3) grown under LDs. Seed mass is the average value of five sample batches with each containing 1000 seeds. For flowering time, seed area and seed mass, data are presented as means ± s.d. of 10, 100 and 5 biological replicates, respectively. Different lowercase letters above the columns indicate the significant difference among different groups (one-way ANOVA, Tukey post-test, P < 0.05). All exact P values are shown in Source Data Extended Data Fig. 8.

Source data

Extended Data Fig. 9 Localization of AP2 expression in developing seeds under LDs.

RNA in situ hybridization of AP2 in seeds at torpedo (left) and bent cotyledon (right) stages using the AP2 antisense or sense probe. Scale bar, 50 µm. EP, epidermis; EM, embryo. Each experiment was repeated three times with similar results.

Extended Data Fig. 10 AP2 mediates photoperiod-regulated seed size in Arabidopsis.

a, Seed area of Col-0 and ap2-12 grown under LDs and SDs. Data are presented as means ± s.d. of 100 biological replicates. b, RT–qPCR analysis of AP2 expression in developing seeds of Col-0 and co-9 grown under LDs and SDs. c, RT–qPCR analysis of AP2 expression in 4 DAP seeds of wild-type (Ler) and co-2 35S:CO-GR (CO-GR) treated with 10 μM Dex or mock at ZT16 under LDs and SDs, respectively. UBQ10 serves as an internal control. Data are presented as means ± s.d. of 3 biological replicates. Asterisks indicate significant difference compared with control groups (two-tailed Student’s t-test, **P < 0.01). All exact P values are shown in Source Data Extended Data Fig. 10.

Source data

Supplementary information

Supplementary Information

Supplementary Figs. 1–8.

Reporting Summary

Supplementary Table

Supplementary Table 1. Differentially expressed genes in 4 DAP seeds of Col-0 and co-9 grown under LDs. Supplementary Table 2. Gene ontology (GO) analysis of genes regulated by CO. Supplementary Table 3. Differentially expressed genes in 4 DAP seeds of Col-0 and 35S:CO grown under LDs. Supplementary Table 4. Differentially expressed genes in 4 DAP seeds of Col-0 and ap2-12 grown under LDs. Supplementary Table 5. Differentially expressed genes in 4 DAP seeds of Col-0 and co-9 ap2-12 grown under LDs. Supplementary Table 6. Co-regulated genes in 4 DAP seeds of ap2-12 and co-9 ap2-12 grown under LDs. Supplementary Table 7. GO analysis of the genes co-regulated in 4 DAP seeds of ap2-12 and co-9 ap2-12 grown under LDs. Supplementary Table 8. KEGG analysis of the genes co-upregulated in 4 DAP seeds of ap2-12 and co-9 ap2-12 grown under LDs. Supplementary Table 9. KEGG analysis of the genes co-downregulated in 4 DAP seeds of ap2-12 and co-9 ap2-12 grown under LDs. Supplementary Table 10. List of primers and DNA sequences used in this study.

Supplementary Data

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Yu, B., He, X., Tang, Y. et al. Photoperiod controls plant seed size in a CONSTANS-dependent manner. Nat. Plants 9, 343–354 (2023). https://doi.org/10.1038/s41477-023-01350-y

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