Chloroplast genomic characterization and phylogenetic analysis of Pellionia scabra / 生物工程学报

Pellionia scabra belongs to the genus Pellionia in the family of Urticaceae, and is a high-quality wild vegetables with high nutritional value. In this study, high-throughput techniques were used to sequence, assemble and annotate the chloroplast genome. We also analyzed its structure, and construct the phylogenetic trees from the P. scabra to further study the chloroplast genome characteristics. The results showed that the chloroplast genome size was 153 220 bp, and the GC content was 36.4%, which belonged to the typical tetrad structure in P. scabra. The chloroplast genome encodes 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes in P. scabra. Among them, 15 genes contained 1 intron, 2 genes contained 2 introns, and rps12 had trans-splicing, respectively. In P. scabra, chloroplast genomes could be divided into four categories, including 43 photosynthesis, 64 self-replication, other 7 coding proteins, and 4 unknown functions. A total of 51 073 codons were detected in the chloroplast genome, among which the codon encoding leucine (Leu) accounted for the largest proportion, and the codon preferred to use A and U bases. There were 72 simple sequence repeats (SSRs) in the chloroplast genome of P. scabra, containing 58 single nucleotides, 12 dinucleotides, 1 trinucleotide, and 1 tetranucleotide. The ycf1 gene expansion was present at the IRb/SSC boundary. The phylogenetic trees showed that P. scabra (OL800583) was most closely related to Elatostema stewardii (MZ292972), Elatostema dissectum (MK227819) and Elatostema laevissimum var. laevissimum (MN189961). Taken together, our results provide worthwhile information for understanding the identification, genetic evolution, and genomics research of P. scabra species.

Characteristics of complete chloroplast genome and phylogenetic analysis of Cirsium souliei (Asteraceae) / 药学学报

italic>Cirsium souliei (Asteraceae) is a perennial medicinal herb of Cirsium with important medicinal and ecological values. Here, we sequenced the complete chloroplast (cp) genome of C. souliei based on high-throughput sequencing technology, then assembled and annotated it, and analysed the structure and characteristics of the cp genome. The result indicated that the cp genome of C. souliei was a typical quadripartite circular structure of 152 470 bp in length, and GC content was 37.7%. The cp genome of C. souliei encoded 134 genes, including 89 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Meanwhile, we detected 188 simple sequence repeats (SSR) loci in the cp genome, which were mainly composed of mononucleotide repeats. Codon bias analysis showed that leucine (Leu) was the highest amino acids with frequency (10.51%), and there were 30 codons with the value of relative synonymous codon usage (RSCU) above one, of which mostly ended with A/U. Additionally, the result from phylogenetic analysis based on 46 cp genomes of Carduoideae showed that C. souliei and C. vulgare were sister species, and had the closest relationship with 100% bootstrap within Cirsium. This study provides theoretical basis for future studying genetic diversity, population genetic structure, systematics and evolution, and speciation mechanism.

Complete chloroplast genome of Sophora alopecuroides (Papilionoideae): molecular structures, comparative genome analysis and phylogenetic analysis

Sophora alopecuroides belongs to the genus Sophora of the family Papilionoideae. It is mainly distributed in the desert and semidesert areas of northern China, and has high medicinal value and ecological function. Previous studies have reported the chemical composition and ecological functions of S. alopecuroides. However, only a few reports are available on the genomic information of S. alopecuroides, especially the chloroplast genome, which greatly limits the study of the evolutionary relationship between other species of Papilionoideae. Here, we report the complete chloroplast genome of S. alopecuroides. The size of the chloroplast genome is 155,207 bp, and the GC content is 36.44%. The S. alopecuroides chloroplast genome consists of 132 genes, including 83 protein-coding genes, 41 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. Phylogenetic analysis revealed the taxonomic position of S. alopecuroidesin Papilionoideae, and the genus Sophora and the genus Ammopiptanthus were highly related. Comparative genomics analysis revealed the gene rearrangement in the evolution of S. alopecuroides. The comparison between S. alopecuroides and the species of the Papilionoideae identified a novel 23 kb inversion between the trnC-GCA and trnF-GAA which occurred before the divergence of Sophora and Ammopiptanthus of Thermopsideae. This study provided an essential data for the understanding of phylogenetic status of S. alopecuroides.