Comparative analysis of codon usage patterns in chloroplast genomes of six <i>Euphorbiaceae</i> species

Abstract

<i>Euphorbiaceae</i> plants are important as suppliers of biodiesel. In the current study, the codon usage patterns and sources of variance in chloroplast genome sequences of six different <i>Euphorbiaceae</i> plant species have been systematically analyzed. Our results revealed that the chloroplast genomes of six <i>Euphorbiaceae</i> plant species were biased towards A/T bases and A/T-ending codons, followed by detection of 17 identical high-frequency codons including GCT, TGT, GAT, GAA, TTT, GGA, CAT, AAA, TTA, AAT, CCT, CAA, AGA, TCT, ACT, TAT and TAA. It was found that mutation pressure was a minor factor affecting the variation of codon usage, however, natural selection played a significant role. Comparative analysis of codon usage frequencies of six <i>Euphorbiaceae</i> plant species with four model organisms reflected that <i>Arabidopsis thaliana</i>, <i>Populus trichocarpa</i>, and <i>Saccharomyces cerevisiae</i> should be considered as suitable exogenous expression receptor systems for chloroplast genes of six <i>Euphorbiaceae</i> plant species. Furthermore, it is optimal to choose <i>Saccharomyces cerevisiae</i> as the exogenous expression receptor. The outcome of the present study might provide important reference information for further understanding the codon usage patterns of chloroplast genomes in other plant species.