The genus Lancea is native to the Qinghai-Tibetan Plateau and consists of two species, Lancea tibetica Hook. f. et Thoms. and Lancea hirsuta Bonati. Here, we report the complete sequences of the chloroplast genomes of L. tibetica and L. hirsuta, which were 153,665 and 154,045 bp in length, respectively, and each included a pair of inverted repeated regions (25,624 and 25,838 bp in length, respectively) that were separated by a large single copy region (84,401 and 84,588 bp in length, respectively) and a smaller single copy region (18,016 and 17,781 bp in length, respectively). A total of 106 genes in L. tibetica and 105 in L. hirsuta comprised 79 protein-coding genes, and 4 ribosomal RNA (rRNA) genes, as well as 23 and 22 transfer RNA (tRNA) genes in L. tibetica and L. hirsuta, respectively. The gene order, content, and orientation of the two Lancea chloroplast genomes exhibited high similarity. A large number of informative repetitive sequences, including SSRs, were observed in both genomes. Comparisons of the genomes with those of three other Lamiales species revealed 12 highly divergent regions in the intergenic spacers and in the matK, rpoA, rps19, ndhF, ccsA, ndhD, and ycf1 coding regions. A phylogenomic analysis suggested that Lancea forms a monophyletic group that is closely related to the clade composed of the families Phrymaceae, Paulowniaceae, and Rehmanniaceae.

Trigonella foenum-graecum L. is a Leguminosae plant, and the stems, leaves, and seeds of this plant are rich in chemical components that are of high research value. The chloroplast (cp) genome of T. foenum-graecum has been reported, but the mitochondrial (mt) genome remains unexplored. In this study, we used second- and third-generation sequencing methods, which have the dual advantage of combining high accuracy and longer read length. The results showed that the mt genome of T. foenum-graecum was 345,604 bp in length and 45.28% in GC content. There were 59 genes, including: 33 protein-coding genes (PCGs), 21 tRNA genes, 4 rRNA genes and 1 pseudo gene. Among them, 11 genes contained introns. The mt genome codons of T. foenum-graecum had a significant A/T preference. A total of 202 dispersed repetitive sequences, 96 simple repetitive sequences (SSRs) and 19 tandem repetitive sequences were detected. Nucleotide diversity (Pi) analysis counted the variation in each gene, with atp6 being the most notable. Both synteny and phylogenetic analyses showed close genetic relationship among Trifolium pratense, Trifolium meduseum, Trifolium grandiflorum, Trifolium aureum, Medicago truncatula and T. foenum-graecum. Notably, in the phylogenetic tree, Medicago truncatula demonstrated the highest level of genetic relatedness to T. foenum-graecum, with a strong support value of 100%. The interspecies non-synonymous substitutions (Ka)/synonymous substitutions (Ks) results showed that 23 PCGs had Ka/Ks < 1, indicating that these genes would continue to evolve under purifying selection pressure. In addition, setting the similarity at 70%, 23 homologous sequences were found in the mt genome of T. foenum-graecum. This study explores the mt genome sequence information of T. foenum-graecum and complements our knowledge of the phylogenetic diversity of Leguminosae plants.

Thalictrum baicalense Turcz. ex Ledeb. is a well-known herbaceous perennid that has been used as a traditional medicine to treat influenza, hepatitis, and detoxfeaction. In this study, we release and detail the complete chloroplast genome sequences of T. baicalense. The whole chloroplast genome was 155,859 bp in length and comprised 130 genes, including 84 protein-coding genes, 37 tRNA genes, eight rRNA genes. The T. baicalense chloroplast genome had a GC content of 38.39%. The phylogenetic relationships inferred that T. baicalense, T. tenue, T. minus and T. petaloideum are closely related to each other within the genus Thalictrum.

Objectives: Codon usage bias is a fundamental feature of gene expression that can influence evolutionary processes and genetic diversity. This study aimed to investigate the mitochondrial codon usage characteristics and their driving forces in three Medicago species: Medicago polymorpha, Medicago sativa, and Medicago truncatula. Methods: The complete mitochondrial genome sequences of the three species were downloaded from GenBank, and 21 shared coding sequences were screened. Codon usage patterns were analyzed using CodonW 1.4.2 and CUSP software. Key parameters, including the relative synonymous codon usage (RSCU), effective number of codons (ENC), codon adaptation index (CAI), codon bias index (CBI), and frequency of optimal codons (Fop), were calculated. Phylogenetic trees and RSCU clustering maps were constructed to explore evolutionary relationships. Results: The GC contents of the mitochondrial genomes followed the order of GC1 > GC2 > GC3. ENC values averaged above 35, while CAI, CBI, and Fop values ranged from 0.160 to 0.161, −0.078 to −0.076, and 0.362 to 0.363, respectively, indicating a weak preference for codons ending with A/U. Correlation and neutrality analyses suggested that codon usage bias was influenced by both mutation pressure and natural selection, with natural selection being the dominant factor. Fifteen optimal codons, predominantly ending with A/U, were identified. Phylogenetic analysis confirmed the close relationship among the three Medicago species, consistent with traditional taxonomy, whereas the RSCU clustering did not align with the phylogenetic relationships. Conclusions: This study provides insights into the mitochondrial codon usage patterns and their evolutionary determinants in Medicago species, highlighting the predominant role of natural selection in shaping codon usage bias. The findings offer a foundation for comparative genomic studies and evolutionary analyses and may be beneficial for improving genetic engineering and breeding programs of Medicago species.

Pterygocalyx volubilis Maxim. (Gentianaceae) is a traditional Chinese medicine, and its whole grass is used in the treatment of pulmonary tuberculosis and other conditions. Here, the complete chloroplast genome sequence of P. volubilis was reported based on the Illumina HiSeq Platform. The chloroplast genome genome is 154,365 bp in length, containing a pair of inverted repeated (IR) regions (25,928 bp) that are separated by a large single copy (LSC) region of 84,033 bp, and a small single copy (SSC) region of 18,476 bp. Moreover, a total of 130 functional genes were annotated, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. In the maximum-likelihood (ML) phylogenetic tree, Pterygocalyx clustered with the genus Swertia. This sequenced chloroplast genome of P. volubilis supports that Pterygocalyx belongs to subtribe Swertiinae.

Background: As an important class of E3 ubiquitin ligases in the ubiquitin proteasome pathway, proteins containing homologous E6-AP carboxyl terminus (HECT) domains are crucial for growth, development, metabolism, and abiotic and biotic stress responses in plants. However, little is known about HECT genes in wheat (Triticum aestivum L.), one of the most important global crops. Methods: Using a genome-wide analysis of high-quality wheat genome sequences, we identified 25 HECT genes classified into six groups based on the phylogenetic relationship among wheat, rice, and Arabidopsis thaliana. Results: The predicted HECT genes were distributed evenly in 17 of 21 chromosomes of the three wheat subgenomes. Twenty-one of these genes were hypothesized to be segmental duplication genes, indicating that segmental duplication was significantly associated with the expansion of the wheat HECT gene family. The Ka/Ks ratios of the segmental duplication of these genes were less than 1, suggesting purifying selection within the gene family. The expression profile analysis revealed that the 25 wheat HECT genes were differentially expressed in 15 tissues, and genes in Group II, IV, and VI (UPL8, UPL6, UPL3) were highly expressed in roots, stems, and spikes. This study contributes to further the functional analysis of the HECT gene family in wheat.