Characteristics and Phylogeny of the Myricaria germanica Chloroplast Genome

Purpose To analyze the structural characteristics and gene information of Myricaria germanica chloroplast genome and its phylogenetic relationship in Tamaricaceae.

Methods The chloroplast genome of M. germanica was sequenced based on NGS platform, the genome was assembled and annotated combined with multiple bioinformatics tools, and the repetitive sequences, simple sequence repeat (SSR), codon preference and phylogeny were analyzed.

Results The total length of M. germanica chloroplast genome was 154749 bp, with a quadripartite circular structure, including a small single copy region of 18213 bp, a large single copy region of 84600 bp, and two inverted repeat regions of 25968 bp. Total GC content was 36.21%. There were a total of 134 annotated genes, including 89 protein coding genes, eight rRNA genes and 37 tRNA genes. A total of 39 long terminal repeats and 51 SSR loci were identified. A total of 64 types of codons were detected with a total usage frequency of 51583. The codon preference showed that the highest frequency of leucine codon usage was 5250, the lowest was tryptophan (678) , and the relative synonymous codon usage of AGA codon was the highest (1.86). The phylogenetic analysis showed that the genus Myricaria was monophyletic and formed a sister group with the genus Tamarix. M. germanica was a sister group to M. bracteata, M. squamosa and M. paniculata. Meanwhile, molecular evidence supported that M. paniculata and M. laxiflora were independent species.

Conclusion This study elucidates the characteristics of M. germanica chloroplast genome and reconstructs the phylogenetic relationships of species within the genus Myricaria, providing a basis for the development of molecular markers, species identification and adaptive evolution research of the genus Myricaria.