Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes

Abstract Plastid genomes (plastomes) have a quadripartite structure, but some species have drastically reduced or lost inverted repeat (IR) regions. IR regions are important for genome stability and the evolution rate. In the evolutionary process of gymnosperms, the typical IRs of conifers were lost...

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Main Authors: Jingyao Ping, Jing Hao, Jinye Li, Yiqing Yang, Yingjuan Su, Ting Wang
Format: Article
Language:English
Published: Wiley 2022-01-01
Series:Ecology and Evolution
Subjects:
Online Access:https://doi.org/10.1002/ece3.8499
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author Jingyao Ping
Jing Hao
Jinye Li
Yiqing Yang
Yingjuan Su
Ting Wang
author_facet Jingyao Ping
Jing Hao
Jinye Li
Yiqing Yang
Yingjuan Su
Ting Wang
author_sort Jingyao Ping
collection DOAJ
description Abstract Plastid genomes (plastomes) have a quadripartite structure, but some species have drastically reduced or lost inverted repeat (IR) regions. IR regions are important for genome stability and the evolution rate. In the evolutionary process of gymnosperms, the typical IRs of conifers were lost, possibly affecting the evolutionary rate and selection pressure of genomic protein‐coding genes. In this study, we selected 78 gymnosperm species (51 genera, 13 families) for evolutionary analysis. The selection pressure analysis results showed that negative selection effects were detected in all 50 common genes. Among them, six genes in conifers had higher ω values than non‐conifers, and 12 genes had lower ω values. The evolutionary rate analysis results showed that 9 of 50 common genes differed between conifers and non‐conifers. It is more obvious that in non‐conifers, the rates of psbA (trst, trsv, ratio, dN, dS, and ω) were 2.6‐ to 3.1‐fold of conifers. In conifers, trsv, ratio, dN, dS, and ω of ycf2 were 1.2‐ to 3.6‐fold of non‐conifers. In addition, the evolution rate of ycf2 in the IR was significantly reduced. psbA is undergoing dynamic change, with an abnormally high evolution rate as a small portion of it enters the IR region. Although conifers have lost the typical IR regions, we detected no change in the substitution rate or selection pressure of most protein‐coding genes due to gene function, plant habitat, or newly acquired IRs.
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spelling doaj.art-4723e7bee3bc459391cf5b0a1f9f9cf82023-02-15T09:06:07ZengWileyEcology and Evolution2045-77582022-01-01121n/an/a10.1002/ece3.8499Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genesJingyao Ping0Jing Hao1Jinye Li2Yiqing Yang3Yingjuan Su4Ting Wang5College of Life Sciences South China Agricultural University Guangzhou ChinaCollege of Life Sciences South China Agricultural University Guangzhou ChinaCollege of Life Sciences South China Agricultural University Guangzhou ChinaCollege of Life Science and Technology Central South University of Forestry and Technology Changsha ChinaSchool of Life Sciences Sun Yat‐sen University Guangzhou ChinaCollege of Life Sciences South China Agricultural University Guangzhou ChinaAbstract Plastid genomes (plastomes) have a quadripartite structure, but some species have drastically reduced or lost inverted repeat (IR) regions. IR regions are important for genome stability and the evolution rate. In the evolutionary process of gymnosperms, the typical IRs of conifers were lost, possibly affecting the evolutionary rate and selection pressure of genomic protein‐coding genes. In this study, we selected 78 gymnosperm species (51 genera, 13 families) for evolutionary analysis. The selection pressure analysis results showed that negative selection effects were detected in all 50 common genes. Among them, six genes in conifers had higher ω values than non‐conifers, and 12 genes had lower ω values. The evolutionary rate analysis results showed that 9 of 50 common genes differed between conifers and non‐conifers. It is more obvious that in non‐conifers, the rates of psbA (trst, trsv, ratio, dN, dS, and ω) were 2.6‐ to 3.1‐fold of conifers. In conifers, trsv, ratio, dN, dS, and ω of ycf2 were 1.2‐ to 3.6‐fold of non‐conifers. In addition, the evolution rate of ycf2 in the IR was significantly reduced. psbA is undergoing dynamic change, with an abnormally high evolution rate as a small portion of it enters the IR region. Although conifers have lost the typical IR regions, we detected no change in the substitution rate or selection pressure of most protein‐coding genes due to gene function, plant habitat, or newly acquired IRs.https://doi.org/10.1002/ece3.8499conifergymnosperminverted repeat regionrate heterogeneityselection pressure
spellingShingle Jingyao Ping
Jing Hao
Jinye Li
Yiqing Yang
Yingjuan Su
Ting Wang
Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
Ecology and Evolution
conifer
gymnosperm
inverted repeat region
rate heterogeneity
selection pressure
title Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
title_full Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
title_fullStr Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
title_full_unstemmed Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
title_short Loss of the IR region in conifer plastomes: Changes in the selection pressure and substitution rate of protein‐coding genes
title_sort loss of the ir region in conifer plastomes changes in the selection pressure and substitution rate of protein coding genes
topic conifer
gymnosperm
inverted repeat region
rate heterogeneity
selection pressure
url https://doi.org/10.1002/ece3.8499
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