CsKDO is a candidate gene regulating seed germination lethality in cucumber

Seed germination plays an important role in the initial stage of plant growth. However, few related studies focused on lethality after seed germination in plants. In this study, we identified an Ethyl methanesulfonate (EMS) mutagenesis mutant Csleth with abnormal seed germination in cucumber (Cucumis sativus L.). The radicle of the Csleth mutant grew slowly and detached from the cotyledon until 14 d after sowing. Genetic analysis showed that the mutant phenotype of Csleth was controlled by a single recessive gene. MutMap(+) and Kompetitive Allele Specific PCR (KASP) genotyping results demonstrated that Csa3G104930 encoding 3-deoxy-manno-octulosonate cytidylyltransferase (CsKDO) was the candidate gene of the Csleth mutant. The transition mutation of aspartate occurred in Csa3G104930 co-segregated with the phenotyping data. CsKDO was highly expressed in male flowers in wild type cucumbers. Subcellular localization results showed that CsKDO was located in the nucleus. Overall, these results suggest CsKDO regulates lethality during seed germination in cucumber.