两个 APETALA2 家族成员介导的转录级联反应调控番茄中的类胡萝卜素生物合成。
A transcriptional cascade mediated by two APETALA2 family members orchestrates carotenoid biosynthesis in tomato.
机构信息
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
Life Science and Technology School, Lingnan Normal University, Zhanjiang, 524048, China.
出版信息
J Integr Plant Biol. 2024 Jun;66(6):1227-1241. doi: 10.1111/jipb.13650. Epub 2024 Mar 28.
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.
类胡萝卜素是人体健康的重要营养物质,必须从植物中获得,因为人体无法合成它们。解析植物中类胡萝卜素代谢的调控机制是通过分子设计育种来操纵植物中类胡萝卜素含量的第一步。在这项研究中,我们确定 SlAP2c,一个 APETALA2(AP2)家族成员,作为一个转录抑制因子来调节番茄(Solanum lycopersicum)中的类胡萝卜素生物合成。在“MicroTom”和“Ailsa Craig”背景下敲除 SlAP2c 导致番茄红素积累增加,而过量表达该基因导致果实呈橙色成熟,但番茄红素含量明显低于野生型。我们确定 SlAP2c 通过直接结合其启动子中的顺式元件来抑制参与番茄红素生物合成的基因的表达。此外,SlAP2c 依赖其 EAR 基序招募共抑制子 TOPLESS(TPL)2/4,并与组蛋白去乙酰化酶(had)1/3 形成复合物,从而降低番茄红素生物合成基因的组蛋白乙酰化水平。此外,SlAP2a,SlAP2c 的同源物,在果实成熟过程中在上游作用于 SlAP2c,并通过抑制 SlAP2c 转录来减轻 SlAP2c 对番茄红素生物合成基因的抑制作用。因此,我们鉴定了一个由 AP2 家族成员介导的转录级联反应,该反应调节番茄果实成熟过程中的番茄红素生物合成,为植物中类胡萝卜素代谢的操纵奠定了基础。