Comparative chloroplast genomics between the invasive weed Mikania micrantha and its indigenous congener Mikania cordata: Structure variation, identification of highly divergent regions, divergence time estimation, and phylogenetic analysis.
Comparative chloroplast genomics between the invasive weed Mikania micrantha and its indigenous congener Mikania cordata: Structure variation, identification of highly divergent regions, divergence time estimation, and phylogenetic analysis.
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DOI：
10.1016/j.ympev.2018.04.015
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发表时间：
2018-09
影响因子：
4.1
通讯作者：
Yingjuan Su;Lu Huang;Zhen Wang;Ting Wang
中科院分区：
文献类型：
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作者：
Yingjuan Su;Lu Huang;Zhen Wang;Ting Wang
Mikania micranthaandMikania cordataare the only two species in genusMikania(Asteraceae) in China. They share very similar morphological and life-history characteristics but occupy quite different habitats. Most importantly, they generate totally different ecological consequences. WhileM. micranthahas become an exotic invasive weed,M. cordataexists as an indigenous species with no harmful effects on native plants or habitats. As a continuous study of our previously reportedM. micranthachloroplast (cp) genome, in this study we have further sequenced theM. cordatacp genome to (1) conduct a comparative genome analysis to gain insights into the mechanism of invasiveness; (2) develop cp markers to examine the population genetic adaptation ofM. micrantha; and (3) screen variable genome regions of phylogenetic utility. TheM. cordatachloroplast genome is 151,984 bp in length and displays a typical quadripartite structure. The number and distribution of protein coding genes, tRNA genes, and rRNA genes ofM. cordataare identical to those ofM. micrantha. The main difference lays in that the pseudogenization ofndhFand a 118-bp palindromic repeat only arises inM. cordata. Fourteen highly divergent regions, 235 base substitutions, and 58 indels were identified between the two cp genomes. Phylogenetic inferences revealed a sister relationship betweenM. micranthaandM. cordatawhose divergence was estimated to occur around 1.78 million years ago (MYA). Twelve cpSSR loci were detected to be polymorphic and adopted to survey the genetic adaptation ofM. micranthapopulations. No cpSSR loci were found to undergo selection. Our results build a foundation to examine the invasive mechanism ofMikaniaweed.
