Camphora Fabr. is a genus in the family Lauraceae, comprising over 20 tropical and subtropical tree species. Since the genera Camphora and Cinnamomum Schaeff. were described, there has been a long-lasting controversy regarding the phylogenetic relationships among taxa in both genera. In particular, phylogenetic inferences derived from plastid data remain debated, with varying hypotheses proposed and occasional disputes concerning the monophyly of Camphora taxa. To further investigate the relationships, We analyzed plastomes and nuclear ribosomal cistron sequences (nrDNA) of 22 Camphora taxa, 15 Cinnamomum taxa, and 13 representative taxa of related genera. The Camphora plastomes range from 152,745 to 154,190 bp, with a GC content of 39.1% to 39.2%. A total of 128 genes were identified in the Camphora plastomes, including 84 protein-coding genes, 8 rRNA genes, and 36 tRNA genes. A total of 1130 SSR loci were detected from plastomes of Camphora, and A/T base repeats looked like the most common. Comparative analyses revealed that the plastomes of Camphora exhibit high similarity in overall structure. The loci ycf1, ycf2, trnK (UUU), psbJ-psbL, and ccsA-ndhD were identified as candidate DNA barcodes for these taxa. Plastome phylogenetic analysis revealed that Camphora is not monophyletic, whereas the nrDNA dataset supported the monophyly of Camphora. We propose that intergeneric hybridization may underlie the observed discordance between plastid and nuclear data in Camphora, and we recommend enhanced taxonomic sampling and precise species identification to improve phylogenetic resolution and accuracy.

Camellia azalea is an endemic species within the genus Camellia that exhibits the trait of summer flowering, which is of significant ornamental and research value. Nevertheless, research on the regulatory mechanisms of flower formation in C. azalea is still limited, so in this study, transcriptome sequencing and analysis of endogenous hormone contents were conducted at three distinct growth stages: floral induction, floral organ maturation, and anthesis. Illumina sequencing yielded a total of 20,643 high-quality unigenes. Comparative analyses of representative samples from the three growth stages identified 6681, 1925, and 8400 differentially expressed genes (DEGs), respectively. These DEGs were further analyzed for functional enrichment using the GO and KEGG databases. Additionally, core genes from each flowering pathway underwent expression pattern analysis and network diagram construction. This revealed that the flower development process in C. azalea is linked to the specific expression of the genes involved in the photoperiod, temperature, and autonomous pathways and is subject to comprehensive regulation by multiple pathways. Further analysis of the dynamic trends of five endogenous hormone contents and plant hormone signal transduction genes revealed significant differences in the requirements of endogenous hormones, such as gibberellins and indoleacetic acid, by C. azalea at distinct growth stages. Additionally, the majority of genes on the phytohormone signal transduction pathway demonstrated a high correlation with the changes in the contents of each hormone. The present study integrates physiological and molecular approaches to identify key genes and metabolic pathways that regulate the summer flowering of C. azalea, thereby laying a theoretical foundation for further investigations into its flowering mechanism and related functional genes.

Impatiens walleriana is a widely cultivated ornamental species extensively used in landscaping and garden design, with its vibrant floral colors constituting one of the primary determinants of its ornamental value. We found in preliminary observations that treatment of I. walleriana seeds with colchicine at 60 mg L⁻¹ induced significant flower color variation, with petals changing from purple to pink. Based on this, the present study used the wild-type (purple) and induced mutant plants (pink) of I. walleriana as materials, and systematically elucidated the molecular regulatory mechanism underlying its flower color variation via integrated analysis of targeted metabolomics and transcriptomics. Metabolomic analysis identified 84 anthocyanin-related metabolites. Metabolite composition and accumulation levels differed significantly between Iw-MU and Iw-WT. Pelargonidin, peonidin, and petunidin were markedly elevated in Iw-MU, while procyanidins accumulated to higher levels in Iw-WT. These metabolic differences may serve as the key metabolic basis for the petal color transition to pink. Transcriptomic analysis identified a total of 689 differentially expressed genes, of which 386 were upregulated and 303 were downregulated. Subsequent functional annotation and enrichment analysis revealed that the flavonoid biosynthesis pathway played a key regulatory role in flower color variation. Among these, the significant downregulation of key anthocyanin biosynthetic genes, DFR and ANS, likely suppressed the production of colored anthocyanins. In contrast, the expression levels of ANR and LAR genes were significantly upregulated, which may drive the metabolic flux to shift toward proanthocyanidin biosynthesis. This study elucidated the metabolomic composition characteristics and key regulatory genes associated with the floral color transition from pinkish-purple to light pink in I. walleriana, as well as clarified the core metabolic pathways and molecular regulatory mechanisms underlying this variation. These findings provide a theoretical foundation for the genetic improvement of flower color and the breeding of new cultivars in I. walleriana.