RÉSUMÉ
ObjectiveTo obtain high-quality chloroplast genome information on Stemona tuberosa and clarify its structure， sequence features， and phylogenetic status. MethodThe Illumina NovaSeq 6000 and PacBio RS Ⅱ platforms were used for library construction and sequencing of S. tuberosa， respectively. The data from both sequencing platforms were combined and subjected to bioinformatics analysis for genome assembly and base correction， resulting in a high-quality chloroplast genome. Subsequently， sequence features， repetitive sequences， gene diversity， and phylogeny were analyzed. ResultThe chloroplast genome size of S. tuberosa was determined to be 154 379 bp. The structure of the chloroplast genome followed the typical quadripartite circular form， consisting of a pair of inverted repeat regions （IRs） with a length of 27 074 bp， a small single-copy region （SSC） of 17 924 bp， and a large single-copy region （LSC） of 82 307 bp. The average GC content was 37.86%. A total of 121 genes were annotated， including 30 tRNA genes， four rRNA genes， and 87 protein-coding genes. Among them， six tRNA genes and 12 protein-coding genes contained introns. In the chloroplast genome of S. tuberosa， 49 long repetitive sequences and 59 single-nucleotide simple sequence repeats （SSRs） were identified. Comparative analysis of chloroplast genomes among four Stemona species revealed high diversity in the ycf1 and ndhF genes. The phylogenetic tree constructed based on the chloroplast genome showed consistent classification with the current taxonomic status of S. tuberosa. ConclusionThe high-quality chloroplast genome of S. tuberosa was successfully assembled， providing valuable information on the structure and sequence features of chloroplast genomes in four Stemona species， including S. tuberosa. These findings lay a foundation for the identification， evolution， and phylogenetic studies of medicinal plants in the genus Stemona.
RÉSUMÉ
DNA barcoding has been widely used for herb identification in recent decades,enabling safety and innovation in the field of herbal medicine.In this article,we summarize recent progress in DNA bar-coding for herbal medicine to provide ideas for the further development and application of this tech-nology.Most importantly,the standard DNA barcode has been extended in two ways.First,while conventional DNA barcodes have been widely promoted for their versatility in the identification of fresh or well-preserved samples,super-barcodes based on plastid genomes have rapidly developed and have shown advantages in species identification at low taxonomic levels.Second,mini-barcodes are attractive because they perform better in cases of degraded DNA from herbal materials.In addition,some mo-lecular techniques,such as high-throughput sequencing and isothermal amplification,are combined with DNA barcodes for species identification,which has expanded the applications of herb identification based on DNA barcoding and brought about the post-DNA-barcoding era.Furthermore,standard and high-species coverage DNA barcode reference libraries have been constructed to provide reference se-quences for species identification,which increases the accuracy and credibility of species discrimination based on DNA barcodes.In summary,DNA barcoding should play a key role in the quality control of traditional herbal medicine and in the international herb trade.
RÉSUMÉ
The many-banded krait, Bungarus multicinctus, has been recorded as the animal resource of JinQianBaiHuaShe in the Chinese Pharmacopoeia. Characterization of its venoms classified chief phyla of modern animal neurotoxins. However, the evolutionary origin and diversification of its neurotoxins as well as biosynthesis of its active compounds remain largely unknown due to the lack of its high-quality genome. Here, we present the 1.58 Gbp genome of B. multicinctus assembled into 18 chromosomes with contig/scaffold N50 of 7.53 Mbp/149.8 Mbp. Major bungarotoxin-coding genes were clustered within genome by family and found to be associated with ancient local duplications. The truncation of glycosylphosphatidylinositol anchor in the 3'-terminal of a LY6E paralog released modern three-finger toxins (3FTxs) from membrane tethering before the Colubroidea divergence. Subsequent expansion and mutations diversified and recruited these 3FTxs. After the cobra/krait divergence, the modern unit-B of β-bungarotoxin emerged with an extra cysteine residue. A subsequent point substitution in unit-A enabled the β-bungarotoxin covalent linkage. The B. multicinctus gene expression, chromatin topological organization, and histone modification characteristics were featured by transcriptome, proteome, chromatin conformation capture sequencing, and ChIP-seq. The results highlighted that venom production was under a sophisticated regulation. Our findings provide new insights into snake neurotoxin research, meanwhile will facilitate antivenom development, toxin-driven drug discovery and the quality control of JinQianBaiHuaShe.
RÉSUMÉ
ObjectiveTo identify the molecular biology of various species of Tibetan Codonopsis plants based on internal transcribed spacer（ITS）2 and psbA-trnH sequence barcode technology. MethodThe genomic DNA of 28 Tibetan Codonopsis plant samples from four species （Codonopsis canescens，C. foetens subsp. nervosa，C. pilosula， and C. thalictrifolia var. mollis） were extracted，and the ITS2 and psbA-trnH sequences were amplified and sequenced. The related sequences of 81 Tibetan Codonopsis plant samples belonging to 15 species were downloaded from GenBank， and MEGA 6.0 was used for sequence comparison and mutation site analysis. The GC content and genetic distance within and between species were calculated. Additionally， phylogenetic trees were constructed by maximum likelihood （ML） method， neighbor-joining （NJ） method，and unweighted pair-group method with arithmetic means （UPGMA） . ResultAccording to the mutation site，C. canescens， C. pilosula，C. pilosula subsp. tangshen， C. pilosula var. modesta，C. bhutanica，C. clematidea，C. lanceolata，C. subglobosa and C. foetens were distinguished. In the phylogenetic trees，the optimal clustering effects for ITS2 and psbA-trnH sequences were obtained using the ML method and the UPGMA method， respectively， and 12 species were effectively clustered. ConclusionITS2 and psbA-trnH sequences have a high identification rate for species of single origin，but there are still some limitations in identifying variants and original variants. This study provides basis for the identification of affinity relationship and clinical safety of Tibetan Codonopsis plants.