Novel Genomic Regions of Wilt Resistance in Bottle Gourd [ (Mol.) Standl.] Discovered in Genome-Wide Association Study.

wilt (FW) is a typical soil-borne disease that seriously affects the yield and fruit quality of bottle gourd. Thus, to improve resistance to FW in bottle gourd, the genetic mechanism underlying FW resistance needs to be explored. In this study, we performed a genome-wide association study (GWAS) based on 5,330 single-nucleotide polymorphisms (SNPs) and 89 bottle gourd accessions. The GWAS results revealed a total of 10 SNPs ( ≤ 0.01, -log ≥ 2.0) significantly associated with FW resistance that were detected in at least two environments (2019DI, 2020DI, and the average across the 2 years); these SNPs were located on chromosomes 1, 2, 3, 4, 8, and 9. Linkage disequilibrium (LD) block structure analysis predicted three potential candidate genes for FW resistance. Genes and were within the range of the mean LD block of the marker BGReSe_14202; gene was 280 kb upstream of the marker BGReSe_00818. Real-time quantitative PCR (qRT-PCR) analysis showed that was significantly up-regulated in FW-infected plants of YD-4, Yin-10, and Hanbi; and were specifically up-regulated in FW-infected plants of YD-4. Therefore, gene is likely the major effect candidate gene for resistance against FW in bottle gourd. This work provides scientific evidence for the exploration of candidate gene and development of functional markers in FW-resistant bottle gourd breeding programs.