Zou Qi, Bao Tiantian, Yu Lei, Xu Haifeng, Liu Wenjun, Li Zhiqiang, Zhu Yansong, Chen Ran, Hou Xukai, Zhang Zongying, Wang Nan, Chen Xuesen
College of Horticulture Sciences and Engineering, Shandong Agricultural University, Tai'an, Shandong, China.
Tai'an Academy of Agricultural Sciences, Tai'an, Shandong, China.
Plant Biotechnol J. 2025 Apr;23(4):1101-1117. doi: 10.1111/pbi.14567. Epub 2025 Jan 7.
Apple (Malus domestica Borkh.) is one of the most economically valuable fruit crops globally and a key dietary source for various nutrients. However, the levels of ascorbic acid (AsA) and anthocyanin, essential micronutrients for human health, are extremely low in the pulp of commonly cultivated apple varieties. In the present study, the second-generation hybrid strain of Xinjiang red-fleshed apple ('Zihong No. 1' × 'Gala') was used as the test material. The results revealed that AsA content was significantly higher in red-fleshed apple pulp than in non-red-fleshed varieties, and the expression of MdGLDH, a key gene in the D-mannose/L-galactose pathway, correlated strongly with AsA levels. Using the promoter of MdGLDH as bait, an R3-type MYB transcription factor (TF), MdCPC-like, was identified through yeast one-hybrid screening. Further analysis revealed that the overexpression of MdCPCL increased the AsA and anthocyanin levels in both callus and fruits, whereas MdCPCL knockdown led to a reduction in their levels. Moreover, the interaction between MdCPCL and the bHLH TF MdILR3-like was confirmed, forming the MdCPCL-MdILR3L complex. This complex significantly enhanced the transcription of downstream target genes MdGLDH and MdANS, promoting the synthesis of AsA and anthocyanins. This study contributes to further enrich the anabolic pathways of AsA and anthocyanin in apples and provides a theoretical foundation for the quality breeding of red-fleshed apple varieties.
苹果（Malus domestica Borkh.）是全球经济价值最高的水果作物之一，也是多种营养物质的重要饮食来源。然而，常见栽培苹果品种的果肉中，对人体健康至关重要的微量营养素抗坏血酸（AsA）和花青素含量极低。在本研究中，以新疆红肉苹果的第二代杂交品系（‘紫宏1号’ב嘎啦’）为试验材料。结果表明，红肉苹果果肉中的AsA含量显著高于非红肉品种，且D-甘露糖/L-半乳糖途径中的关键基因MdGLDH的表达与AsA水平密切相关。以MdGLDH的启动子为诱饵，通过酵母单杂交筛选鉴定出一个R3型MYB转录因子（TF）MdCPC-like。进一步分析表明，MdCPCL的过表达增加了愈伤组织和果实中的AsA和花青素水平，而MdCPCL的敲低导致其水平降低。此外，证实了MdCPCL与bHLH转录因子MdILR3-like之间的相互作用，形成了MdCPCL-MdILR3L复合物。该复合物显著增强了下游靶基因MdGLDH和MdANS的转录，促进了AsA和花青素的合成。本研究有助于进一步丰富苹果中AsA和花青素的合成途径，并为红肉苹果品种的品质育种提供理论基础。
