Paraboea (Gesneriaceae) distributed in the karst areas of South and Southwest China and Southeast Asia, is an ideal genus to study the phylogeny and adaptive evolution of karst plants. In this study, the complete chloroplast genomes of twelve Paraboea species were sequenced and analyzed. Twelve chloroplast genomes ranged in size from 153166 to 154245 bp. Each chloroplast genome had a typical quartile structure, and relatively conserved type and number of gene components, including 131 genes which are composed of 87 protein coding genes, 36 transfer RNAs and 8 ribosomal RNAs. A total of 600 simple sequence repeats and 389 non-overlapped sequence repeats were obtained from the twelve Paraboea chloroplast genomes. We found ten divergent regions (trnH-GUG-psbA, trnM-CAU, trnC-GCA, atpF-atpH, ycf1, trnK-UUU-rps16, rps15, petL, trnS-GCU-trnR-UCU and psaJ-rpl33) among the 12 Paraboea species to be potential molecular markers. In the phylogenetic tree of 31 Gesneriaceae plants including twelve Paraboea species, all Paraboea species clustered in a clade and confirmed the monophyly of Paraboea. Nine genes with positive selection sites were detected, most of which were related to photosynthesis and protein synthesis, and might played crucial roles in the adaptability of Paraboea to diverse karst environments. These findings are valuable for further study of the phylogeny and karst adaptability of Gesneriaceae plants.

Numerous species of Ardisia are widely used for their medicinal and ornamental values in China. However, accurately identifying Ardisia species at the molecular level remains a challenge due to the morphological similarities among different species, the complexity of interspecific variation, and the limited availability of genetic markers. In this study, we reported 20 chloroplast genomes of Ardisia species from China and combined them with 8 previously published chloroplast genomes to conduct a comprehensive analysis for phylogenetic relationships and adaptive evolution. For the 28 Ardisia species analyzed in this study, the size of the chloroplast genomes ranged from 155,088 bp to 156,999 bp, and all exhibited a typical tetrad structure with conserved gene content and number. Each genome contained 85–88 protein-coding genes, 36–37 tRNA genes, and 8 rRNA genes. Comparative analysis showed that the genomic structures and gene order were relatively conserved with slight variations in the inverted repeat regions (IRs). Simple sequence repeats (SSRs) were predominantly single nucleotide repeats, while repeat sequences were mainly composed of palindromic and forward repeats. Twelve highly variable regions were identified as potential DNA barcodes for species identification and phylogenetic analysis of Ardisia. The phylogenetic tree supported the division of the subgenus Bladhia s.l. into two subgenera: Bladhia s.str. and Odontophylla (Yang) Huang. Further investigation revealed that two protein-coding genes (rbcL and rpoC2) were under positive selection and might be associated with the adaptation of Ardisia species to shaded environments. Our study analyzed the chloroplast genomes of 20 Ardisia species from China to explore their phylogenetic relationships and adaptive evolution. By combining these results with data from eight previously published chloroplast genomes, the essential characteristics of Ardisia chloroplast genomes were clarified. The research establishes a theoretical basis for the classification, identification, and comprehension of the adaptive evolution of Ardisia species.

Catechins includ galloylated catechins and non-galloylated catechins, among which galloylated catechins exhibit stronger antioxidant, anti-inflammatory and anti-cancer activities. Section Chrysantha Chang, the only group of yellow Camellia with rich catechins in their flowers, is a common health drink in southern China. To date, few studies have examined galloylated catechins biosynthesis in flowers of this group. To enrich the genetic information of the galloylated catechins biosynthesis, the ONT sequencing platform was used to perform full-length transcriptome sequencing of C. perpetua flowers and 7,972,574 transcripts was identified, including 42,883 simple sequence repeats (SSRs), 41,961 coding sequences (CDSs) and 2,602 long non-coding RNAs (lncRNAs). 36,516 transcripts were successfully annotated, and 147 critical enzyme-encoding genes were identified as involved in the galloylated catechins biosynthesis pathway, including 17 CpSCPL1A genes. Bioinformatics analysis revealed that each CpSCPL1A protein consisted of 427-506 amino acids, and all CpSCPL1A proteins were divided into 5 groups with conserved motifs 1, 4, 5, 6 and 8. Based on the correlation analysis between the gene expression of 17 CpSCPL1A genes and the content of galloylated catechins, 11 candidate CpSCPL1A genes were identified to be involved in the biosynthesis of 4 types of galloylated catechins in C. perpetua flowers. The results enrich the transcriptome data for C. perpetua and provide valuable insights into the importance of the CpSCPL1A gene family members in the galloylated catechins biosynthesis.

Maesa perlarius (Loureiro) Merrill 1935, a perennial evergreen shrub in the genus Maesa (family Primulaceae), commonly known as ‘Jiyudan’, is a medicinally important plant of ethnopharmacological i...