The areca nut (Areca catechu L.) is a prominent tropical and subtropical crop of economic importance renowned for its significant medicinal value. It is recognized as one of the most prominent components of the four traditional Southern Chinese medicines. However, the lack of comprehensive genetic diversity data and reliable molecular markers has posed challenges in assessing and improving the areca nut germplasm for breeding programs. This study analyzed 196 areca nut materials, employing 40,173 high-quality single-nucleotide polymorphisms (SNPs) to evaluate the genetic relationships among the samples. Population structure analysis identified three distinct groups based on the optimal K-value, with the principal component analysis (PCA) results consistent with the results of population structure division. A phylogenetic tree constructed using the neighbor-joining method revealed clear separations among the samples based on their geographic origins. The nucleotide diversity (π) values ranged from 2.46 × 10⁻⁵ to 5.71 × 10⁻⁵, indicating limited genetic diversity within the areca nut population. The pairwise population differentiation index (Fst) revealed moderate genetic differentiation among the groups. The discovery of these SNPs will be helpful for areca nut conservation and utilization. The results of this study indicate the limited genetic diversity within areca nut germplasm resources, providing insights for management and breeding.

Litchi (Litchi chinensis Sonn.) is a high-value subtropical fruit crop prized for its unique flavor and nutritional profile. UDP-glycosyltransferases (UGTs) catalyze the glycosylation of diverse small molecules and play critical roles in fruit development, secondary metabolism, and stress responses, yet this gene family has not been systematically characterized in litchi. Here, we identified 102 LcUGT genes across the 15 litchi chromosomes and classified them into ten phylogenetic subfamilies. Duplication analysis indicated that whole-genome/segmental and tandem duplications were the major drivers. By integrating 212 public RNA-seq samples spanning diverse tissues, developmental stages, and stress conditions, we constructed a comprehensive expression atlas of the LcUGT family and identified candidate genes with divergent spatiotemporal patterns during fruit development. Co-expression network analysis further revealed tissue-specific modules, hub UGTs, and candidate upstream transcription factors associated with aril and seed development, and qRT-PCR assays in an additional cultivar showed expression trends consistent with the transcriptome data. This study provides the first genome-wide characterization of the litchi UGT gene family and offers candidate targets for molecular breeding of fruit quality and stress tolerance.