J Integr Plant Biol ›› 2024, Vol. 66 ›› Issue (6): 1227-1241.DOI: 10.1111/jipb.13650

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  • 收稿日期:2023-11-24 接受日期:2024-03-06 出版日期:2024-06-01 发布日期:2024-06-25

A transcriptional cascade mediated by two APETALA2 family members orchestrates carotenoid biosynthesis in tomato

Xiaoqing He1†, Kaidong Liu2†, Yi Wu1, Weijie Xu1, Ruochen Wang1, Julien Pirrello3, Mondher Bouzayen3, Mengbo Wu1 and Mingchun Liu1*   

  1. 1. Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China;
    2. Life Science and Technology School, Lingnan Normal University, Zhanjiang 524048, China;
    3. Laboratoire de Recherche en Sciences Végétales—Génomique et Biotechnologie des Fruits—UMR5546, Université de Toulouse, CNRS, UPS, Toulouse-INP, Toulouse 31013, France
    These authors contributed equally to this work.
    *Correspondence: Mingchun Liu (mcliu@scu.edu.cn)
  • Received:2023-11-24 Accepted:2024-03-06 Online:2024-06-01 Published:2024-06-25

Abstract: Carotenoids are important nutrients for human health that must be obtained from plants since they cannot be biosynthesized by the human body. Dissecting the regulatory mechanism of carotenoid metabolism in plants represents the first step toward manipulating carotenoid contents in plants by molecular design breeding. In this study, we determined that SlAP2c, an APETALA2 (AP2) family member, acts as a transcriptional repressor to regulate carotenoid biosynthesis in tomato (Solanum lycopersicum). Knockout of SlAP2c in both the “MicroTom” and “Ailsa Craig” backgrounds resulted in greater lycopene accumulation, whereas overexpression of this gene led to orange-ripe fruit with significantly lower lycopene contents than the wild type. We established that SlAP2c represses the expression of genes involved in lycopene biosynthesis by directly binding to the cis-elements in their promoters. Moreover, SlAP2c relies on its EAR motif to recruit the co-repressors TOPLESS (TPL)2/4 and forms a complex with histone deacetylase (had)1/3, thereby reducing the histone acetylation levels of lycopene biosynthesis genes. Furthermore, SlAP2a, a homolog of SlAP2c, acts upstream of SlAP2c and alleviates the SlAP2c-induced repression of lycopene biosynthesis genes by inhibiting SlAP2c transcription during fruit ripening. Therefore, we identified a transcriptional cascade mediated by AP2 family members that regulates lycopene biosynthesis during fruit ripening in tomato, laying the foundation for the manipulation of carotenoid metabolism in plants.

Key words: APETALA2 family members, carotenoid biosynthesis, tomato, transcriptional cascade

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