摘要Low-temperature(LT)stress threatens cucumber production globally;however,the molecular mech-anisms underlying LT tolerance in cucumber remain largely unknown.Here,using a genome-wide as-sociation study(GWAS),we found a naturally oc-curring single nucleotide polymorphism(SNP)in the STAYGREEN(CsSGR)coding region at the gLTT5.1 locus associated with LT tolerance.Knockout mu-tants of CsSGR generated by clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated nuclease 9 exhibit enhanced LT tolerance,in particularly,increased chlorophyll(Chl)content and reduced reactive oxygen species(ROS)accumulation in response to LT.Moreover,the C-repeat Binding Factor 1(CsCBF1)tran-scription factor can directly activate the expression of CsSGR.We demonstrate that the LT-sensitive haplotype CsSGRHapA,but not the LT-tolerant hap-lotype CsSGRHapG could interact with NON-YELLOW COLORING 1(CsNYC1)to mediate Chl degradation.Geographic distribution of the CsSGR haplotypes indicated that the CsSGRHapG was se-lected in cucumber accessions from high latitudes,potentially contributing to LT tolerance during cu-cumber cold-adaptation in these regions.CsSGR mutants also showed enhanced tolerance to sal-inity,water deficit,and Pseudoperonospora cu-bensis,thus CsSGR is an elite target gene for breeding cucumber varieties with broad-spectrum stress tolerance.Collectively,our findings provide new insights into LT tolerance and will ultimately facilitate cucumber molecular breeding.