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Article|01 May 2021|OPEN
The AaCBF4-AaBAM3.1 module enhances freezing tolerance of kiwifruit (Actinidia arguta)
Shihang Sun1,2, Chungen Hu2, Xiujuan Qi1, Jinyong Chen1, Yunpeng Zhong1, Abid Muhammad1, Miaomiao Lin1, & Jinbao Fang1,
1Key Laboratory for Fruit Tree Growth, Development and Quality Control, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, China
2Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China

Horticulture Research 8,
Article number: 97 (2021)
doi: 10.1038/hortres.2021.97
Views: 213

Received: 10 Nov 2020
Revised: 20 Jan 2021
Accepted: 24 Feb 2021
Published online: 01 May 2021

Abstract

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.