CmERFIV-4-CmWRKY44-CmPSY1 调节乙烯诱导的 β-胡萝卜素在东方甜瓜果实中的积累
Postharvest Biology and Technology ( IF 6.4 ) Pub Date : 2025-01-25 , DOI: 10.1016/j.postharvbio.2025.113409
Fei Luo , Xiaoyu Duan , Ge Gao , Yaping Zhao , Meng Li , Hongyan Qi
东方甜瓜果色橙色，典型的更年期水果，主要积累β-胡萝卜素。然而，乙烯和 β-胡萝卜素积累之间的关系仍不清楚。在这里，在开花后 25 天（果实变色初始阶段）用乙烯和 1-MCP 处理橙色果肉甜瓜果实的 'HDB'。结果表明，外源乙烯促进乙烯生成、β-胡萝卜素含量和 β-胡萝卜素生物合成基因表达上调。分析 CmPSY1 启动子特征，鉴定转录因子 （TF） CmWRKY44。同时，CmWRKY44 位于细胞核中，其表达被乙烯上调。EMSA 、 Y1H 、 GUS、荧光素酶报告基因测定和根癌农杆菌介导的瞬时转化进一步表明 CmWRKY44 可以与 CmPSY1 启动子结合并正向调节其基因表达。此外，筛选酵母单杂交文库，发现了 CmERFIV-4，一个细胞核 TF，并被乙烯诱导。最后，EMSA、Y1H、荧光素酶报告基因和 GUS 实验显示，CmERFIV-4 通过靶向其启动子激活 CmWRKY44 基因的表达。总的来说，外源乙烯可以通过 CmERFIV-4 和 CmWRKY44 在东方甜瓜中的级联反应加速β-胡萝卜素的积累，这为更年期甜瓜果实中类胡萝卜素的代谢提供了理论依据。
CmERFIV-4-CmWRKY44-CmPSY1 modulates ethylene-induced β-carotene accumulation in oriental melon fruit
Oriental melon with orange flesh color, a typical climacteric fruit, mainly accumulated β-carotene. However, the relationship between ethylene and β-carotene accumulation is still unclear. Here, ‘HDB’ with orange fleshed melon fruit were treated with ethylene and 1-MCP at 25 days after anthesis (fruit color transformation initial stage). The results showed exogenous ethylene promotes ethylene production, β-carotene content and up-regulated β-carotene biosynthesis genes expression. The CmPSY1 promoter characteristics were analyzed, and the transcription factor (TF) CmWRKY44 was identified. Meanwhile, CmWRKY44 located in the nucleus and its expression was up-regulated by ethylene. The EMSA, Y1H, GUS, luciferase reporter assay and the Agrobacterium tumefaciens-mediated transient transformation further indicated CmWRKY44 could bind to CmPSY1 promoter and positively regulate its gene expression. Furthermore, screening yeast one-hybrid library, the CmERFIV-4 was discovered, a nucleus TF, and induced by ethylene. Finally, EMSA, Y1H, luciferase reporter and GUS assay showed that CmERFIV-4 activated the CmWRKY44 gene expression by targeted its promoter. Collectively, exogenous ethylene could accelerate β-carotene accumulation though cascade of CmERFIV-4 and CmWRKY44 in oriental melon, which provide theoretical basis for carotenoid metabolism in climacteric melon fruit.
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