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Article|02 Dec 2022|OPEN
VabHLH137 promotes proanthocyanidin and anthocyanin biosynthesis and enhances resistance to Colletotrichum gloeosporioides in grapevine
Dan Yu1 , Wei Wei2 , Zhongqi Fan2 , Jianye Chen2 , Yilin You1 , Weidong Huang1 and Jicheng Zhan,1 ,
1Beijing Key Laboratory of Viticulture and Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100085, China
2State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
*Corresponding author. E-mail: zhanjicheng@cau.edu.cn

Horticulture Research 10,
Article number: uhac261 (2023)
doi: https://doi.org/10.1093/hr/uhac261
Views: 90

Received: 18 Jul 2022
Accepted: 20 Nov 2022
Published online: 02 Dec 2022

Abstract

Proanthocyanidins (PAs) and anthocyanins are involved in the response of plants to various environmental stresses. However, the mechanism behind defense-induced PA biosynthetic regulation is still not completely elucidated, also in grapevine. This study performed a transcriptome sequencing analysis of grape berries infected with Colletotrichum gloeosporioides to highlight the induction of the VabHLH137 factor from the basic helix–loop–helix (bHLH) XII subfamily by the fungus, which appeared to be significantly co-expressed with PA-related genes. The functional analysis of VabHLH137 overexpression and knockdown in transgenic grape calli showed that it positively regulated PA and anthocyanin biosynthesis. Moreover, VabHLH137 overexpression in the grape calli significantly increased resistance to C. gloeosporioides. A yeast one-hybrid and electrophoretic mobility shift assay revealed that VabHLH137 directly bound to the VaLAR2 promoter, enhancing its activity and interacting with VaMYBPAR, a transcriptional activator of PA biosynthesis. Furthermore, transient experiments showed that although the VabHLH137 + VaMYBPAR complex activated VaLAR2 expression, it failed to further enhance VaLAR2 expression compared to VaMYBPAR alone. The findings indicated that VabHLH137 enhanced PA biosynthesis by activating of VaLAR2 expression, providing new insight into the transcriptional regulation of defense-induced PA biosynthesis in grapevine.