Lin Han, Bai Lijuan, Wei Wei, Su Wenbing, Wu Yanting, Wu Rong, Wang Hui, Chen Jianye, Lin Hetong, Fan Zhongqi
Institute of Postharvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Fruit Research Institute, Fujian Academy of Agricultural Science, Fuzhou 350013, China.
Foods. 2024 Mar 11;13(6):854. doi: 10.3390/foods13060854.
Banana is a typical cold-sensitive fruit; it is prone to chilling injury (CI), resulting in a quality deterioration and commodity reduction. However, the molecular mechanism underlying CI development is unclear. In this study, cold storage (7 °C for 5 days) was used to induce CI symptoms in bananas. As compared with the control storage (22 °C for 5 days), cold storage increased the CI index and cell membrane permeability. Moreover, we found that the expression levels of the WRKY transcription factor were increased consistently with the progression of CI development. A subcellular localization assay revealed that MaWRKY70 was localized in the nucleus. Transcriptional activation analyses showed that MaWRKY70 processed a transactivation ability. Further, an electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter (DLR) assays showed that MaWRKY70 was directly bound to the W-box motifs in the promoters of four lipoxygenase (LOX) genes associated with membrane lipid degradation and activated their transcription. Collectively, these findings demonstrate that MaWRKY70 activates the transcription of , thereby acting as a possible positive modulator of postharvest CI development in banana fruit.
香蕉是典型的冷敏型水果；它容易受到冷害（CI），导致品质下降和商品价值降低。然而，冷害发生的分子机制尚不清楚。在本研究中，采用冷藏（7℃处理5天）诱导香蕉出现冷害症状。与对照贮藏（22℃处理5天）相比，冷藏增加了冷害指数和细胞膜通透性。此外，我们发现WRKY转录因子的表达水平随着冷害发展进程持续升高。亚细胞定位分析表明MaWRKY70定位于细胞核。转录激活分析表明MaWRKY70具有反式激活能力。进一步地，电泳迁移率变动分析（EMSA）和双荧光素酶报告（DLR）分析表明，MaWRKY70直接结合到与膜脂降解相关的四个脂氧合酶（LOX）基因启动子中的W-盒基序上，并激活它们的转录。总的来说，这些发现表明MaWRKY70激活了 的转录，从而可能作为香蕉果实采后冷害发展的一个正向调节因子。
