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Article|01 Jul 2020|OPEN
Transcriptional profiling reveals multiple defense responses in downy mildew-resistant transgenic grapevine expressing a TIR-NBS-LRR gene located at the MrRUN1/MrRPV1 locus
Junjie Qu1, Ian Dry2, Lulu Liu1, Zexi Guo1 & Ling Yin1,
1Guangxi Crop Genetic Improvement and Biotechnology Key Lab, Guangxi Academy of Agricultural Sciences, Nanning 530007, China
2CSIRO Agriculture & Food, Wine Innovation West Building, Locked Bag 2, Glen Osmond, SA 5064, Australia

Horticulture Research 8,
Article number: 161 (2021)
doi: 10.1038/hortres.2021.161
Views: 114

Received: 30 Nov 2020
Revised: 22 Apr 2021
Accepted: 04 May 2021
Published online: 01 Jul 2020

Abstract

Grapevine downy mildew (DM) is a destructive oomycete disease of viticulture worldwide. MrRPV1 is a typical TIR-NBS-LRR type DM disease resistance gene cloned from the wild North American grapevine species Muscadinia rotundifolia. However, the molecular basis of resistance mediated by MrRPV1 remains poorly understood. Downy mildew-susceptible Vitis vinifera cv. Shiraz was transformed with a genomic fragment containing MrRPV1 to produce DM-resistant transgenic Shiraz lines. Comparative transcriptome analysis was used to compare the transcriptome profiles of the resistant and susceptible genotypes after DM infection. Transcriptome modulation during the response to P. viticola infection was more rapid, and more genes were induced in MrRPV1-transgenic Shiraz than in wild-type plants. In DM-infected MrRPV1-transgenic plants, activation of genes associated with Ca2+ release and ROS production was the earliest transcriptional response. Functional analysis of differentially expressed genes revealed that key genes related to multiple phytohormone signaling pathways and secondary metabolism were highly induced during infection. Coexpression network and motif enrichment analysis showed that WRKY and MYB transcription factors strongly coexpress with stilbene synthase (VvSTS) genes during defense against P. viticola in MrRPV1-transgenic plants. Taken together, these findings indicate that multiple pathways play important roles in MrRPV1-mediated resistance to downy mildew.