关键词: 木兰科, 叶绿体基因组, 密码子使用, 系统进化树

Abstract: Magnoliaceae is primitive angiosperm with important economic, medicinal and ornamental values. Codon is the core element of translation in central dogma, and its characterics analysis of coding region is important to study the gene function and phylogeneitc evolution. At present, 29 chloroplast genomes of Magnoliaceae have been successfully assembled and annotated. Therefore, this paper collected the chloroplast genomes of Magnoliaceae and systematically analyzed the codon usage profiling of chloroplast genomesand decoded the phylogenetic relationship among the 29 Magnoliaceae plants. The results illustrated that synonymous codons and optimal codons in 29 chloroplast genomes from Magnoliaceae had the same codon usage preference and ending with A/U. The natural selection was the main factor in codon preference. Furthermore, the phylogenetic trees from 29 Magnoliaceae chloroplasts was constructed by using whole genome sequences, CDS sequences and codon preference RSCU values, respectively. It was found that the phylogenetic relationship from codon usage preference was significantly different with others, while the phylogenetic trees from chloroplast whole genomes and CDS sequences were closer to the true relationship among 29 Magnoliaceae plants. Those results further supported that the base mutation and non-coding sequences played an important role in the evolution process of organisms.

Key words: Magnoliaceae, chloroplast genome, codon usage, phylogenetic tree