High-density linkage map construction and QTL mapping of Botrytis cinerea resistance in the Vitis genus using whole-genome resequencing

• QTL mapping studies have focused specifically on gray mold resistance in grapevine remain limited. • A genetic linkage map was constructed by using whole-genome resequencing which spanned 2518.11 cM and comprised 4854 high-quality bin markers, with an average marker interval of 0.52 cM. • A stable QTL on LG8 within a 0.3 cM confidence interval was identified, four receptor-like protein (RLP) genes ( VvRLP32, VvRLP34, VvRLP53 , and VvRLP6 ) and two transcription factors, VvWRKY32 and a MYB family member ( At1g14600 ) which related to grape gray mold resitane were discovered in this interval. Gray mold, caused by the necrotrophic fungus Botrytis cinerea , severely affects the yield and quality of grapevine ( Vitis vinifera L.). Breeding grapevine cultivars with enhanced resistance to gray mold and identifying resistance-associated genes are crucial for sustainable grape production. As resistance to gray mold is a quantitative trait governed by multiple minor-effect genes, linkage map construction and quantitative trait loci (QTL) mapping in cross-pollinated populations represent effective strategies for gene discovery in grape germplasm. However, QTL mapping studies have focused specifically on gray mold resistance in grapevine remain limited, limiting our understanding of the genetic loci conferring resistance. In this study, a hybrid population was generated from a highly susceptible cultivar (“Red Globe”) and a highly resistant cultivar (“Bate”). Whole-genome resequencing was performed on both parents and 150 progeny to construct a genetic linkage map. The final map spanned 2518.11 cM and comprised 4854 high-quality bin markers, with an average marker interval of 0.52 cM. QTL mapping identified a stable QTL on LG8 within a 0.3cM confidence interval. Within this region, six candidate genes potentially involved in gray mold resistance were identified, including four receptor-like protein (RLP) genes ( VvRLP32, VvRLP34, VvRLP53 , and VvRLP6 ) and two transcription factors, VvWRKY32 and a MYB family member ( At1g14600 ). The high-density genetic linkage map and candidate genes identified in this study provide a valuable foundation and genetic resource for gray mold resistance breeding in grapevine.