Phylogeny and evolution of chloroplast tRNAs in Adoxaceae

Ecology and Evolution

Jian‐Ni Liu¹  Xiao‐Gang Fu²  Zhong‐Hu Li²  Ming Yue²  Ting‐Ting Zhang²  Tong Zhou²  Qiu‐Yi Zhong² 

[1] Department of Geology State Key Laboratory of Continental Dynamics Early Life Institute Northwest University Xi'an China;Shaanxi Key Laboratory for Animal Conservation Key Laboratory of Resource Biology and Biotechnology in Western China Ministry of Education College of Life Sciences Northwest University Xi'an China;

关键词: anticodon;    chloroplast tRNA;    intron;    phylogeny;    transition/transversion;   

DOI  :  10.1002/ece3.7133

来源: DOAJ

【 摘 要 】

Abstract Chloroplasts are semiautonomous organelles found in photosynthetic plants. The major functions of chloroplasts include photosynthesis and carbon fixation, which are mainly regulated by its circular genomes. In the highly conserved chloroplast genome, the chloroplast transfer RNA genes (cp tRNA) play important roles in protein translation within chloroplasts. However, the evolution of cp tRNAs remains unclear. Thus, in the present study, we investigated the evolutionary characteristics of chloroplast tRNAs in five Adoxaceae species using 185 tRNA gene sequences. In total, 37 tRNAs encoding 28 anticodons are found in the chloroplast genome in Adoxaceae species. Some consensus sequences are found within the Ψ‐stem and anticodon loop of the tRNAs. Some putative novel structures were also identified, including a new stem located in the variable region of tRNATyr in a similar manner to the anticodon stem. Furthermore, phylogenetic and evolutionary analyses indicated that synonymous tRNAs may have evolved from multiple ancestors and frequent tRNA duplications during the evolutionary process may have been primarily caused by positive selection and adaptive evolution. The transition and transversion rates are uneven among different tRNA isotypes. For all tRNAs, the transition rate is greater with a transition/transversion bias of 3.13. Phylogenetic analysis of cp tRNA suggested that the type I introns in different taxa (including eukaryote organisms and cyanobacteria) share the conserved sequences “U‐U‐x2‐C” and “U‐x‐G‐x2‐T,” thereby indicating the diverse cyanobacterial origins of organelles. This detailed study of cp tRNAs in Adoxaceae may facilitate further investigations of the evolution, phylogeny, structure, and related functions of chloroplast tRNAs.

【 授权许可】

Unknown