Vitis rotundifolia Genes Introgressed with RUN1 and RPV1: Poor Recombination and Impact on V. vinifera Berry...

Area of Science:

• Plant genetics and breeding
• Genomics and transcriptomics
• Plant pathology

Background:

• The MrRUN1/MrRPV1 locus introgressed from Vitis rotundifolia confers resistance to downy and powdery mildews in Vitis vinifera.
• Understanding the genomic and transcriptomic consequences of this introgression is crucial for developing resistant grape cultivars.

Purpose of the Study:

• To investigate the impact of Vitis rotundifolia genome introgression on gene expression during grape berry development.
• To identify genes and pathways associated with disease resistance in Vitis vinifera x Vitis rotundifolia hybrids.

Main Methods:

• Comparative RNA-sequencing (RNA-seq) of single berries from Vitis vinifera cultivars and Vitis vinifera x Vitis rotundifolia hybrids.
• Alignment of RNA-seq reads to Vitis vinifera and Vitis rotundifolia reference genomes.
• Weighted Gene Co-expression Network Analysis (WGCNA) to identify gene modules correlated with resistance and berry phenology.

Main Results:

• Differentially expressed genes were classified into modules correlated with resistance or berry traits.
• Resistance-correlated transcripts mapped to a specific region of Vitis rotundifolia chromosome 12 containing the MrRUN1/MrRPV1 locus.
• Overexpressed genes in resistant hybrids involved calcium signaling, hormone signaling, transcription factors, and phenylpropanoid biosynthesis.

Conclusions:

• The introgressed Vitis rotundifolia background significantly alters the transcriptomic landscape of Vitis vinifera hybrids.
• Constitutive expression of certain Vitis rotundifolia genes, including those involved in calcium signaling, contributes to disease resistance.
• This study provides a foundation for understanding disease resistance mechanisms in hybrid grapevines.