Newswise \u2014 Cultivated grapes (Vitis vinifera) are widely grown for wine and table use, but their susceptibility to fungal diseases\u2014particularly in humid climates\u2014remains a persistent challenge. Although breeders have long sought ways to enhance disease resistance, most efforts have focused on improved agronomic traits rather than tapping into wild germplasm. Resistance (R) genes, central to plant immunity, are known to vary greatly between species and can be influenced by nearby transposable elements. The lack of complete, high-quality wild grape genome assemblies has limited our ability to pinpoint such genes. Due to these challenges, there is a critical need to explore wild grape genomes to uncover novel resistance mechanisms.<\/p>\n
In a study (DOI: 10.1093\/hr\/uhae306) <\/a>published on November 6, 2024, in Horticulture Research<\/a>, scientists from the Chinese Academy of Agricultural Sciences reported the phased telomere-to-telomere (T2T) genome assemblies of wild Vitis davidii and the cultivated \u2018Manicure Finger\u2019. Using advanced PacBio HiFi and Hi-C sequencing technologies, the team mapped structural variations and resistance gene clusters at unprecedented resolution. Their research identified unique defense-related loci in the wild grape and revealed differences in gene expression responses to white rot infection, laying the foundation for improved breeding strategies.<\/p>\n The researchers generated complete, haplotype-resolved genome assemblies for both grape accessions. They discovered that Vitis davidii has a lower heterozygosity rate but a larger genome than the cultivated variety, driven primarily by the expansion of transposable elements. Among over 36,000 identified structural variations, many were linked to gene expression differences, particularly in promoter regions. These differences correlated with allele-specific expression patterns, suggesting a functional role in disease response. Analysis of resistance (R) genes revealed eight subtypes, with NBS-type genes showing the most dynamic expression and clustering behavior. Importantly, five large clusters of NBS-type R genes were found exclusively in the wild grape genome\u2014absent in the cultivated variety. Upon infection with Coniella diplodiella, the causal agent of white rot, the team observed robust differential expression of resistance genes in wild grape tissues. Using genetic mapping from a Vd \u00d7 MF F1 population, the researchers identified seven QTLs associated with disease resistance, including three novel loci. Within these QTLs, six NBS-type R genes were pinpointed as key candidates due to their strong expression shifts post-infection. This integrative approach\u2014combining genome assembly, expression analysis, and genetic mapping\u2014provides new insights into the molecular basis of fungal disease resistance in grapes.<\/p>\n \u201cThis study gives us an unprecedented view of the genetic architecture underlying disease resistance in grapes,\u201d said Dr. Ying Zhang, senior author of the study. \u201cBy comparing a highly resistant wild species to a susceptible cultivated variety, we were able to uncover resistance gene clusters and candidate loci that had never been characterized before. Our results not only help us understand the evolutionary dynamics of plant immunity, but also offer powerful genomic tools to guide grapevine breeding in the face of climate change and emerging diseases.\u201d<\/p>\n The findings pave the way for more targeted and efficient grape breeding programs. By identifying resistance loci and their expression patterns, breeders can now employ molecular markers to track these traits in new cultivars. The discovery of specific NBS-type gene clusters in Vitis davidii offers a blueprint for enhancing white rot resistance through marker-assisted selection or genomic editing. As vineyards face increasing disease pressure and environmental stress, leveraging wild grape germplasm will be essential for building sustainable and resilient production systems. This study underscores the growing importance of high-quality genomic data in solving real-world agricultural problems.<\/p>\n ###<\/p>\n References<\/p>\n DOI<\/strong><\/p>\n 10.1093\/hr\/uhae306<\/a><\/p>\n Original Source URL<\/strong><\/p>\n https:\/\/doi.org\/10.1093\/hr\/uhae306<\/a><\/p>\n Funding information<\/strong><\/p>\n This study was funded by the National Key Research and Development Program of China (2021YFD1200200), the Agricultural Science and Technology Innovation Program (CAAS-ASTIP-2021-ZFRI), the National Natural Science Foundation of China (31872057), and the China Agriculture Research System (CARS-29).<\/p>\n