Yang Congji, Shi Jiale, Qin Yuanyuan, Hua ShengQi, Bao Jiancheng, Liu Xueyan, Peng Yuqi, Gu Yige, Dong Wei
State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, China.
School of Life Science, Henan University, Kaifeng, Henan, People's Republic of China.
GM Crops Food. 2025 Dec;16(1):156-170. doi: 10.1080/21645698.2025.2452702. Epub 2025 Jan 14.
Malic acid markedly affects watermelon flavor. Reducing the malic acid content can significantly increase the sweetness of watermelon. An effective solution strategy is to reduce watermelon malic acid content through molecular breeding technology. In this study, we measured the TSS and pH of six watermelon varieties at four growth nodes. The TSS content was very low at 10 DAP and accumulated rapidly at 18, 26, and 34 DAP. Three phosphoenolpyruvate carboxykinase () genes of watermelon were identified and analyzed. The expression was inversely proportional to malate content variations in fruits. In transgenic watermelon plants, overexpressing the gene, malic acid content markedly decreased. In the knockout transgenic watermelon plants, two SNP mutations and one base deletion occurred in the gene, with the malic acid content in the leaves increasing considerably and the PEPCK enzyme activity reduced to half of the wild-type. It is interesting that the gene triggered the closure of leaf stomata under dark conditions in the knockout transgenic plants, which indicated its involvement in stomatal movement. In conclusion, this study provides a gene target for creating innovative new high-sweetness watermelon varieties.
苹果酸显著影响西瓜风味。降低苹果酸含量可显著提高西瓜甜度。一种有效的解决策略是通过分子育种技术降低西瓜苹果酸含量。在本研究中，我们测定了六个西瓜品种在四个生长节点的总可溶性固形物（TSS）和pH值。在开花后天数（DAP）为10天时，TSS含量非常低，而在18、26和34 DAP时迅速积累。鉴定并分析了西瓜的三个磷酸烯醇式丙酮酸羧激酶（）基因。该基因的表达与果实中苹果酸含量的变化呈负相关。在转基因西瓜植株中，过表达该基因，苹果酸含量显著降低。在基因敲除转基因西瓜植株中，该基因发生了两个单核苷酸多态性（SNP）突变和一个碱基缺失，叶片中的苹果酸含量大幅增加，磷酸烯醇式丙酮酸羧激酶（PEPCK）酶活性降至野生型的一半。有趣的是，在基因敲除转基因植株中，该基因在黑暗条件下触发了叶片气孔关闭，这表明它参与了气孔运动。总之，本研究为培育创新型高甜度西瓜新品种提供了一个基因靶点。
