Breakthrough in Powdery Mildew Resistance: New Findings in Vitis piasezkii Genetics

Strategic Insights -

Recent research from the University of California Davis has shed new light on the genetics of powdery mildew resistance in Vitis piasezkii, a Chinese grape accession. Scientists have identified two loci associated with powdery mildew resistance, Ren6 and Ren7, which differ in timing and strength of response to Erysiphe necator. This study offers a high-resolution view of these loci and provides new insights for grapevine breeding.

Key Takeaways:

  • The Vitis piasezkii accession DVIT2027 carries two loci associated with powdery mildew resistance: Ren6 and Ren7, which differ in timing and strength of response to Erysiphe necator.
  • Both loci are consistent with recognition by intracellular immune receptors, and their expression is linked to the presence of nucleotide-binding leucine-rich repeat (NLR) genes.
  • The study used chromosome-scale diploid genomes of DVIT2027 and its parents to resolve both PM-resistant (PMR) and PM-susceptible (PMS) haplotypes at Ren6 and Ren7.
  • Comparative analyses revealed extensive structural variation and complete haplotype specificity among NLRs, with several candidate genes lacking allelic counterparts in PMS haplotypes.
  • Expression profiling across PMR sib-lines identified four and two CC-NBS-LRR genes potentially associated with Ren6 and Ren7, respectively.
  • Sequence graph reconstruction of these loci across multiple V. piasezkii accessions revealed broad intraspecific diversity and DVIT2027-specific nodes, including within candidate NLR genes.
  • The research supports the identification of resistance gene candidates for functional validation and grapevine breeding.

Statistics:

  • Eight F1 sib-lines carrying different Ren6/Ren7 combinations were analyzed.
  • The study used deep resequencing data from nine V. piasezkii accessions, including DVIT2027.
  • The PM-resistant haplotype at Ren6 was associated with 4 CC-NBS-LRR genes.
  • The PM-susceptible haplotype at Ren6 was associated with 2 CC-NBS-LRR genes.

Sources:

  • G3, 2025. "Dissection of the Ren6 and Ren7 powdery mildew resistance loci in Vitis piasezkii DVIT2027 using phased parental-progeny genomes and intraspecific locus graph reconstruction."
  • University of California Davis. "Department of Viticulture and Enology".
  • University of California Davis, Davis, CA 95616, United States.
  • Oxford Univ Press Inc, Journals Dept, 2001 Evans Rd, Cary, NC 27513, USA.