Song Zhe, Li Yukuo, Zhan Xu, Li Xiaohan, Ye Lingshuai, Lin Miaomiao, Wang Ran, Sun Leiming, Chen Jinyong, Fang Jinbao, Wei Feng, Qi Xiujuan
School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, China.
National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.
BMC Plant Biol. 2025 Jan 22;25(1):89. doi: 10.1186/s12870-025-06109-5.
Red Actinidia arguta has recently become highly popular because of its red appearance resulting from anthocyanin accumulation, and has gradually become an important breeding direction. However, regulators involved in anthocyanin biosynthesis have not been fully characterized in A. arguta.
Here, we demonstrated that a key R2R3-MYB transcription factor, AaMYB61-like, plays a crucial role in A. arguta anthocyanin biosynthesis. The RT-qPCR results revealed that transient overexpression of AaMYB61-like in A. arguta fruit at 90-100 DAFB significantly promoted anthocyanin biosynthesis, as did the gene expression levels of AaCHS, AaCHI, AaF3H, AaLDOX, and AaF3GT, whereas the result of VIGS revealed the opposite results in A. arguta fruit at 105-115 DAFB. A transcriptional activation assay indicated that AaMYB61-like exhibited transcriptional activation activity. Y1H and LUC assays revealed that AaMYB61-like activates the promoters of AaCHS, AaLDOX, and AaF3GT. In addition, AabHLH137 was found to be related to fruit color from the transcriptome data. We demonstrated that AaMYB61-like promotes anthocyanin biosynthesis by interacting with AabHLH137 via Y2H, BiFC, and Agrobacterium-mediated co-transformation.
Our study not only reveals the functions of AaMYB61-like and AabHLH137 in anthocyanin regulation, but also broadly enriches color regulation theory, establishing a foundation for clarifying the molecular mechanism of fruit coloration in kiwifruit.
红肉软枣猕猴桃因其因花青素积累而呈现的红色外观最近变得非常受欢迎，并逐渐成为一个重要的育种方向。然而，软枣猕猴桃中参与花青素生物合成的调控因子尚未得到充分表征。
在此，我们证明了一个关键的R2R3-MYB转录因子AaMYB61-like在软枣猕猴桃花青素生物合成中起关键作用。RT-qPCR结果显示，在花后90-100天的软枣猕猴桃果实中瞬时过表达AaMYB61-like显著促进了花青素生物合成，AaCHS、AaCHI、AaF3H、AaLDOX和AaF3GT的基因表达水平也有所提高，而VIGS结果在花后105-115天的软枣猕猴桃果实中显示出相反的结果。转录激活分析表明AaMYB61-like具有转录激活活性。Y1H和LUC分析表明AaMYB61-like激活AaCHS、AaLDOX和AaF3GT的启动子。此外，从转录组数据中发现AabHLH137与果实颜色有关。我们通过Y2H、BiFC和农杆菌介导的共转化证明AaMYB61-like通过与AabHLH137相互作用促进花青素生物合成。
我们的研究不仅揭示了AaMYB61-like和AabHLH137在花青素调控中的功能，还广泛丰富了颜色调控理论，为阐明猕猴桃果实着色的分子机制奠定了基础。
