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For this investigation, the chloroplast genome of Saccharina sp. ye-E from Russia was uncovered and annotated with Illumina sequencing data to examine the phylogenetic relationship of Saccharina in Laminariaceae from a molecular biology perspective. Analysis of the structural characteristics, simple repeat sequence (SSR) loci, relative species differences, codon preference, and phylogenetic relationships was conducted. The results revealed that the chloroplast genome of Saccharina sp. ye-E had a length of 130,624 bp, containing 139 protein-coding genes (PCGs), 6 ribosomal RNAs (rRNAs) and 57 transfer RNAs (tRNAs) genes, and a total GC content of 31.1%. There were 15 SSR loci in the genome. Effective codon number (ENC) and codon adaptation index (CAI) both indicated the strong codon randomness and codon preference. The phylogenetic tree, based on the complete chloroplast genomes of 10 brown algae, showed that four species of Saccharina genus formed a clade, with Saccharina sp. ye-E and Saccharina latissimi having the most related genetic affinity. It is believed that the determination of the chloroplast genome of Saccharina sp. ye-E will be beneficial for future algal genetics evolution and systematic studies in the Laminariaceae.

Background Calanthe (Epidendroideae, Orchidaceae) is a pantropical genus distributed in Asia and Africa. Its species are of great importance in terms of economic, ornamental and medicinal values. However, due to limited and confusing delimitation characters, the taxonomy of the Calanthe alliance (Calanthe, Cephalantheropsis, and Phaius) has not been sufficiently resolved. Additionally, the limited genomic information has shown incongruences in its systematics and phylogeny. In this study, we used illumina platform sequencing, performed a de novo assembly, and did a comparative analysis of 8 Calanthe group species' plastomes: 6 Calanthe and 2 Phaius species. Phylogenetic analyses were used to reconstruct the relationships of the species as well as with other species of the family Orchidaceae. Results The complete plastomes of the Calanthe group species have a quadripartite structure with varied sizes ranging between 150,105bp-158,714bp, including a large single-copy region (LSC; 83,364bp- 87,450bp), a small single-copy region (SSC; 16,297bp -18,586bp), and a pair of inverted repeat regions (IRs; 25,222bp - 26,430bp). The overall GC content of these plastomes ranged between 36.6-36.9%. These plastomes encoded 131-134 differential genes, which included 85-88 protein-coding genes, 37-38 tRNA genes, and 8 rRNA genes. Comparative analysis showed no significant variations in terms of their sequences, gene content, gene order, sequence repeats and the GC content hence highly conserved. However, some genes were lost in C. delavayi (P. delavayi), including ndhC, ndhF, and ndhK genes. Compared to the coding regions, the non-coding regions had more sequence repeats hence important for species DNA barcoding. Phylogenetic analysis revealed a paraphyletic relationship in the Calanthe group, and confirmed the position of Phaius delavayi in the genus Calanthe as opposed to its previous placement in Phaius. Conclusion This study provides a report on the complete plastomes of 6 Cal

Background Calanthe (Epidendroideae, Orchidaceae) is a pantropical genus distributed in Asia and Africa. Its species are of great importance in terms of economic, ornamental and medicinal values. However, due to limited and confusing delimitation characters, the taxonomy of the Calanthe alliance (Calanthe, Cephalantheropsis, and Phaius) has not been sufficiently resolved. Additionally, the limited genomic information has shown incongruences in its systematics and phylogeny. In this study, we used illumina platform sequencing, performed a de novo assembly, and did a comparative analysis of 8 Calanthe group species' plastomes: 6 Calanthe and 2 Phaius species. Phylogenetic analyses were used to reconstruct the relationships of the species as well as with other species of the family Orchidaceae. Results The complete plastomes of the Calanthe group species have a quadripartite structure with varied sizes ranging between 150,105bp-158,714bp, including a large single-copy region (LSC; 83,364bp- 87,450bp), a small single-copy region (SSC; 16,297bp -18,586bp), and a pair of inverted repeat regions (IRs; 25,222bp - 26,430bp). The overall GC content of these plastomes ranged between 36.6-36.9%. These plastomes encoded 131-134 differential genes, which included 85-88 protein-coding genes, 37-38 tRNA genes, and 8 rRNA genes. Comparative analysis showed no significant variations in terms of their sequences, gene content, gene order, sequence repeats and the GC content hence highly conserved. However, some genes were lost in C. delavayi (P. delavayi), including ndhC, ndhF, and ndhK genes. Compared to the coding regions, the non-coding regions had more sequence repeats hence important for species DNA barcoding. Phylogenetic analysis revealed a paraphyletic relationship in the Calanthe group, and confirmed the position of Phaius delavayi in the genus Calanthe as opposed to its previous placement in Phaius. Conclusion This study provides a report on the complete plastomes of 6 Cal