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Article|19 Jan 2022|OPEN
Overexpression of VqWRKY31 enhances powdery mildew resistance in grapevine by promoting salicylic acid signaling and specific metabolite synthesis
Wuchen Yin1,2 ,† , Xianhang Wang1,3 ,† , Hui Liu1,2 , Ya Wang1,2 , Steve van Nocker4 and Mingxing Tu1,2 , Jinghao Fang1,2 , Junqiang Guo1,2 , Zhi Li1,2 , Xiping Wang,1,2 ,
1State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
2Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China
3College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, China
4Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
*Corresponding author. E-mail: wangxiping@nwsuaf.edu.cn
Both authors contributed equally to the study.

Horticulture Research 9,
Article number: uhab064 (2022)
doi: https://doi.org/10.1093/hr/uhab064
Views: 166

Received: 02 Jun 2021
Accepted: 31 Oct 2021
Published online: 19 Jan 2022

Abstract

Powdery mildew (PM), caused by the fungal pathogen Erysiphe necator, is one of the most destructive diseases of grapevine (Vitis vinifera and other Vitis spp.). Resistance to PM is an important goal for cultivar improvement, and understanding the underlying molecular mechanisms conditioning resistance is critical. Here, we report that transgenic expression of the WRKY transcription factor gene VqWRKY31 from the PM-resistant species Vitis quinquangularis conferred resistance to PM in V. vinifera through promoting salicylic acid signaling and specific metabolite synthesis. VqWRKY31 belongs to the WRKY IIb subfamily, and expression of the VqWRKY31 gene was induced in response to E. necator inoculation. Transgenic V. vinifera plants expressing VqWRKY31 were substantially less susceptible to E. necator infection, and this was associated with increased levels of salicylic acid and reactive oxygen species. Correlation analysis of transcriptomic and metabolomic data revealed that VqWRKY31 promoted expression of genes in metabolic pathways and the accumulation of many disease resistance-related metabolites, including stilbenes, flavonoids, and proanthocyanidins. In addition, results indicated that VqWRKY31 can directly bind to the promoters of two structural genes in stilbene synthesis, STS9 and STS48, and activate their expression. Based on our results, we propose a model where VqWRKY31 enhances grapevine PM resistance through activation of salicylic acid defense signaling and promotion of specific disease resistance-related metabolite synthesis. These findings can be directly exploited for molecular breeding strategies to produce PM-resistant grapevine germplasm.