Begonia is the fifth largest genus of angiosperms in the world, and Begonia handelii is a member of the Begonia(Begoniaceae), and is one of the few species with floral fragrance in this genus. However, the chloroplast genome structure and phylogenetic relationship of this species is still unclear. In this study, the chloroplast genome of B. handelii was sequenced by Illumina HiSeq X platform, and the phylogenetic relationship of this species in Begonia was analyzed with related species. The whole chloroplast genome of B. handelii is 169,406 bp in size, which consist one large single-copy region (LSC) with 95,403 bp, one small single-copy region (SSC) with 20,089 bp, and two inverted repeat regions (IR) with 26,957 bp. The GC content of this chloroplast genome is 35.6%. Moreover, 140 genes were found in the chloroplast of B. handelii, including 90 protein-coding genes, 8 rRNA genes, 42 tRNA genes. Phylogenetic analysis showed that B. handelii is closed to B. coptidifolia and B. pulchrifolia. This study lays the foundation for further research on the chloroplast genome evolution of B. handelii chloroplasts.

Background: Siraitia grosvenorii (monk fruit) is a dioecious medicinal crop native to southern China, yet its terpene synthase (TPS) gene family and the molecular basis of floral sexual dimorphism remain unexplored. Methods: Genome-wide identification of the TPS gene family was performed using HMMER and BLAST-based approaches. Phylogenetic classification, gene structure and conserved motif characterization, and comparative synteny analyses were conducted. Transcriptome data from leaves and fruits at different developmental stages were analyzed for tissue-specific expression profiling. Promoter cis-element analysis, protein–protein interaction network prediction, and molecular docking were performed to characterize the fruit-specific candidate SgTPS49. Results: A total of 58 SgTPS genes were identified and classified into six subfamilies, with TPS-a and TPS-b comprising 72.4% of the family. Approximately 88% of SgTPS genes arose from lineage-specific tandem duplication. Female flowers exhibited monoterpene-dominant scents and smaller corollas, whereas male flowers displayed a mid-morning sesquiterpene burst and greater morphological variation. SgTPS49 was specifically upregulated at 20 days post-pollination and possessed a unique promoter architecture devoid of classical hormone-responsive elements. Molecular docking supported its annotation as a putative monoterpene synthase with favorable GPP binding. Conclusions: This study provides the first comprehensive genomic resource for the SgTPS family in S. grosvenorii, reveals significant sexual dimorphism in floral traits, and identifies SgTPS49 as a key candidate for future functional validation.