Characterization of a novel CmUFO mutation affecting floral development in melon

Melon (Cucumis melo L.) is an important horticultural crop, with fruit formation and yield closely linked to the proper development of floral organs. Understanding floral organogenesis in melon is therefore essential for enhancing agricultural productivity. In this study, we identified a mutant with abnormal floral morphology from an EMS-mutagenized melon population. Genetic analysis revealed that this phenotype is controlled by a single recessive gene. Utilizing MutMap+ and linkage analysis, we pinpointed the candidate gene responsible for this trait as the UNUSUAL FLORAL ORGANS (UFO) gene in melon. A single nucleotide polymorphism (C to T) was found to cause a nonsynonymous mutation in a conserved site of the CmUFO protein. Moreover, CRISPR/Cas9-generated CmUFO mutants exhibited phenotypic characteristics consistent with those of EMS-induced mutants. Transcriptomic analysis indicated that a set of genes associated with flower development were down-regulated in the mutant, suggesting that CmUFO plays a conserved role in floral organ development in melon. This study provides valuable insights into the mechanisms underlying floral organogenesis in melon.