Sun Shihang, Hu Chungen, Qi Xiujuan, Chen Jinyong, Zhong Yunpeng, Muhammad Abid, Lin Miaomiao, Fang Jinbao
Key Laboratory for Fruit Tree Growth, Development and Quality Control, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.
Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.
Hortic Res. 2021 May 1;8(1):97. doi: 10.1038/s41438-021-00530-1.
Beta-amylase (BAM) plays an important role in plant resistance to cold stress. However, the specific role of the BAM gene in freezing tolerance is poorly understood. In this study, we demonstrated that a cold-responsive gene module was involved in the freezing tolerance of kiwifruit. In this module, the expression of AaBAM3.1, which encodes a functional protein, was induced by cold stress. AaBAM3.1-overexpressing kiwifruit lines showed increased freezing tolerance, and the heterologous overexpression of AaBAM3.1 in Arabidopsis thaliana resulted in a similar phenotype. The results of promoter GUS activity and cis-element analyses predicted AaCBF4 to be an upstream transcription factor that could regulate AaBAM3.1 expression. Further investigation of protein-DNA interactions by using yeast one-hybrid, GUS coexpression, and dual luciferase reporter assays confirmed that AaCBF4 directly regulated AaBAM3.1 expression. In addition, the expression of both AaBAM3.1 and AaCBF4 in kiwifruit responded positively to cold stress. Hence, we conclude that the AaCBF-AaBAM module is involved in the positive regulation of the freezing tolerance of kiwifruit.
β-淀粉酶（BAM）在植物抗寒胁迫中起重要作用。然而，BAM基因在耐寒性中的具体作用尚不清楚。在本研究中，我们证明了一个冷响应基因模块参与了猕猴桃的耐寒性。在这个模块中，编码功能蛋白的AaBAM3.1的表达受冷胁迫诱导。过表达AaBAM3.1的猕猴桃株系耐寒性增强，在拟南芥中异源过表达AaBAM3.1也产生了类似的表型。启动子GUS活性和顺式元件分析结果预测AaCBF4是一个可调节AaBAM3.1表达的上游转录因子。通过酵母单杂交、GUS共表达和双荧光素酶报告基因检测进一步研究蛋白质-DNA相互作用，证实AaCBF4直接调节AaBAM3.1的表达。此外，猕猴桃中AaBAM3.1和AaCBF4的表达均对冷胁迫产生积极响应。因此，我们得出结论，AaCBF-AaBAM模块参与了猕猴桃耐寒性的正向调节。
