J Integr Plant Biol ›› 2024, Vol. 66 ›› Issue (5): 909-927.DOI: 10.1111/jipb.13615

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  • 收稿日期:2023-04-20 接受日期:2024-01-11 出版日期:2024-05-01 发布日期:2024-05-31

PIF4 interacts with ABI4 to serve as a transcriptional activator complex to promote seed dormancy by enhancing ABA biosynthesis and signaling

Xiaofeng Luo1, 2†, Yujia Dai1, 2†, Baoshan Xian1, 2†, Jiahui Xu1, Ranran Zhang1, Muhammad Saad Rehmani1, Chuan Zheng1, Xiaoting Zhao1, Kaitao Mao1, Xiaotong Ren1, Shaowei Wei1, 2, Lei Wang1, 2, Juan He1, 2, Weiming Tan3, Junbo Du4, Weiguo Liu4, Shu Yuan5 and Kai Shu1, 2*   

  1. 1. Shaanxi Key Laboratory of Qinling Ecological Intelligent Monitoring and Protection, School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710129, China
    2. Research & Development, Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, China
    3. College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
    4. Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu 611130, China
    5. College of Resources, Sichuan Agricultural University, Chengdu 611130, China
    †These authors contributed equally to this work.
    *Correspondence:Kai Shu (kshu@nwpu.edu.cn)
  • Received:2023-04-20 Accepted:2024-01-11 Online:2024-05-01 Published:2024-05-31

Abstract: Transcriptional regulation plays a key role in the control of seed dormancy, and many transcription factors (TFs) have been documented. However, the mechanisms underlying the interactions between different TFs within a transcriptional complex regulating seed dormancy remain largely unknown. Here, we showed that TF PHYTOCHROME-INTERACTING FACTOR4 (PIF4) physically interacted with the abscisic acid (ABA) signaling responsive TF ABSCISIC ACID INSENSITIVE4 (ABI4) to act as a transcriptional complex to promote ABA biosynthesis and signaling, finally deepening primary seed dormancy. Both pif4 and abi4 single mutants exhibited a decreased primary seed dormancy phenotype, with a synergistic effect in the pif4/abi4 double mutant. PIF4 binds to ABI4 to form a heterodimer, and ABI4 stabilizes PIF4 at the protein level, whereas PIF4 does not affect the protein stabilization of ABI4. Subsequently, both TFs independently and synergistically promoted the expression of ABI4 and NCED6, a key gene for ABA anabolism. The genetic evidence is also consistent with the phenotypic, physiological and biochemical analysis results. Altogether, this study revealed a transcriptional regulatory cascade in which the PIF4–ABI4 transcriptional activator complex synergistically enhanced seed dormancy by facilitating ABA biosynthesis and signaling.

Key words: ABA, ABI4, PIF4, seed dormancy and germination, transcriptional complex

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