To decipher the genetic diversity within the cucurbit genus Citrullus, we generated telomere-to-telomere (T2T) assemblies of 27 distinct genotypes, encompassing all seven Citrullus species. This T2T super-pangenome has expanded the previously published reference genome, T2T-G42, by adding 399.2 Mb and 11,225 genes. Comparative analysis has unveiled gene variants and structural variations (SVs), shedding light on watermelon evolution and domestication processes that enhanced attributes such as bitterness and sugar content while compromising disease resistance. Multidisease-resistant loci from Citrullus amarus and Citrullus mucosospermus were successfully introduced into cultivated Citrullus lanatus. The SVs identified in C. lanatus have not only been inherited from cordophanus but also from C. mucosospermus, suggesting additional ancestors beyond cordophanus in the lineage of cultivated watermelon. Our investigation substantially improves the comprehension of watermelon genome diversity, furnishing comprehensive reference genomes for all Citrullus species. This advancement aids in the exploration and genetic enhancement of watermelon using its wild relatives.

Gamma-aminobutyric acid (GABA) is considered an important bioactive compound that improves sleep quality and regulates blood pressure. Tomatoes are an ideal horticultural crop that can accumulate a high level of GABA in fruits. The development of higher-GABA tomatoes has significant market potential. In this study, we edited the SlGAD3 gene to increase GABA content in the dwarf cherry tomato, WEIMEI T102. After transformation using the Agrobacterium-mediated method, we identified several SlGAD3 mutation lines, which showed changed GABA levels compared to the recipient line. Molecular characterization showed stable trait inheritance for multiple generations. The GABA level in fruits also stably accumulated for multiple generations, which significantly increased up to about 1.9 mg/g FW in E13-13. These results indicate that it is feasible to increase the GABA content in dwarf cherry tomatoes by using gene editing technology.

Vine length is a crucial plant architecture trait in watermelon, which determines its height. In this study, we identified a dominant dwarf watermelon mutant by treating G42 with Ethyl methanesulfonate (EMS). In order to clarify the causes of the dwarfism in mutants, genetic statistics, phenotypic observation, and cytological observation were carried out. Meanwhile, individual resequencing combined with molecular markers was used to map the candidate gene. Our results demonstrated that the dwarf mutant exhibited incomplete dominance. The dwarf plants showed a decrease in the number of internodal cells, shortened internodes, and reduced vine length. Gene mapping indicated that the target gene responsible for this mutation was ClTUA, which encodes α-tubulin. A point mutation in the dwarf plants was identified, specifically, a change from C to T at the 1851st base pair. Further experiments, including transcriptome analysis and Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS), revealed that this gene mutation affected auxin synthesis, leading to the dwarfing of the plants. This study provides new germplasm resources and a theoretical foundation for plant architecture breeding in watermelon.